title: Castle

text: Until the 12th century, stone-built and earth and timber castles were contemporary, but by the late 12th century the number of castles being built went into decline. This has been partly attributed to the higher cost of stone-built fortifications, and the obsolescence of timber and earthwork sites, which meant it was preferable to build in more durable stone. Although superseded by their stone successors, timber and earthwork castles were by no means useless. This is evidenced by the continual maintenance of timber castles over long periods, sometimes several centuries; Owain Glyndŵr's 11th-century timber castle at Sycharth was still in use by the start of the 15th century, its structure having been maintained for four centuries.


title: Castle

text: At the same time there was a change in castle architecture. Until the late 12th century castles generally had few towers; a gateway with few defensive features such as arrowslits or a portcullis; a great keep or donjon, usually square and without arrowslits; and the shape would have been dictated by the lay of the land (the result was often irregular or curvilinear structures). The design of castles was not uniform, but these were features that could be found in a typical castle in the mid-12th century. By the end of the 12th century or the early 13th century, a newly constructed castle could be expected to be polygonal in shape, with towers at the corners to provide enfilading fire for the walls. The towers would have protruded from the walls and featured arrowslits on each level to allow archers to target anyone nearing or at the curtain wall.


title: Castle

text: These later castles did not always have a keep, but this may have been because the more complex design of the castle as a whole drove up costs and the keep was sacrificed to save money. The larger towers provided space for habitation to make up for the loss of the donjon. Where keeps did exist, they were no longer square but polygonal or cylindrical. Gateways were more strongly defended, with the entrance to the castle usually between two half-round towers which were connected by a passage above the gateway – although there was great variety in the styles of gateway and entrances – and one or more portcullis.


title: Castle

text: A peculiar feature of Muslim castles in the Iberian Peninsula was the use of detached towers, called Albarrana towers, around the perimeter as can be seen at the Alcazaba of Badajoz. Probably developed in the 12th century, the towers provided flanking fire. They were connected to the castle by removable wooden bridges, so if the towers were captured the rest of the castle was not accessible.


title: Castle

text: When seeking to explain this change in the complexity and style of castles, antiquarians found their answer in the Crusades. It seemed that the Crusaders had learned much about fortification from their conflicts with the Saracens and exposure to Byzantine architecture. There were legends such as that of Lalys – an architect from Palestine who reputedly went to Wales after the Crusades and greatly enhanced the castles in the south of the country – and it was assumed that great architects such as James of Saint George originated in the East. In the mid-20th century this view was cast into doubt. Legends were discredited, and in the case of James of Saint George it was proven that he came from Saint-Georges-d'Espéranche, in France. If the innovations in fortification had derived from the East, it would have been expected for their influence to be seen from 1100 onwards, immediately after the Christians were victorious in the First Crusade (1096–1099), rather than nearly 100 years later. Remains of Roman structures in Western Europe were still standing in many places, some of which had flanking round-towers and entrances between two flanking towers.


title: Castle

text: The castle builders of Western Europe were aware of and influenced by Roman design; late Roman coastal forts on the English "Saxon Shore" were reused and in Spain the wall around the city of Ávila imitated Roman architecture when it was built in 1091. Historian Smail in "Crusading warfare" argued that the case for the influence of Eastern fortification on the West has been overstated, and that Crusaders of the 12th century in fact learned very little about scientific design from Byzantine and Saracen defences. A well-sited castle that made use of natural defences and had strong ditches and walls had no need for a scientific design. An example of this approach is Kerak. Although there were no scientific elements to its design, it was almost impregnable, and in 1187 Saladin chose to lay siege to the castle and starve out its garrison rather than risk an assault.


title: Castle

text: During the late 11th and 12th centuries in what is now south-central Turkey the Hospitallers, Teutonic Knights and Templars established themselves in the Armenian Kingdom of Cilicia, where they discovered an extensive network of sophisticated fortifications which had a profound impact on the architecture of Crusader castles. Most of the Armenian military sites in Cilicia are characterized by: multiple bailey walls laid with irregular plans to follow the sinuosities of the outcrops; rounded and especially horseshoe-shaped towers; finely-cut often rusticated ashlar facing stones with intricate poured cores; concealed postern gates and complex bent entrances with slot machicolations; embrasured loopholes for archers; barrel, pointed or groined vaults over undercrofts, gates and chapels; and cisterns with elaborate scarped drains. Civilian settlement are often found in the immediate proximity of these fortifications. After the First Crusade, Crusaders who did not return to their homes in Europe helped found the Crusader states of the Principality of Antioch, the County of Edessa, the Kingdom of Jerusalem, and the County of Tripoli. The castles they founded to secure their acquisitions were designed mostly by Syrian master-masons. Their design was very similar to that of a Roman fort or Byzantine "tetrapyrgia" which were square in plan and had square towers at each corner that did not project much beyond the curtain wall. The keep of these Crusader castles would have had a square plan and generally be undecorated.


title: Castle

text: While castles were used to hold a site and control movement of armies, in the Holy Land some key strategic positions were left unfortified. Castle architecture in the East became more complex around the late 12th and early 13th centuries after the stalemate of the Third Crusade (1189–1192). Both Christians and Muslims created fortifications, and the character of each was different. Saphadin, the 13th-century ruler of the Saracens, created structures with large rectangular towers that influenced Muslim architecture and were copied again and again, however they had little influence on Crusader castles.


title: Castle

text: In the early 13th century, Crusader castles were mostly built by Military Orders including the Knights Hospitaller, Knights Templar, and Teutonic Knights. The orders were responsible for the foundation of sites such as Krak des Chevaliers, Margat, and Belvoir. Design varied not just between orders, but between individual castles, though it was common for those founded in this period to have concentric defences.


title: Castle

text: The concept, which originated in castles such as Krak des Chevaliers, was to remove the reliance on a central strongpoint and to emphasise the defence of the curtain walls. There would be multiple rings of defensive walls, one inside the other, with the inner ring rising above the outer so that its field of fire was not completely obscured. If assailants made it past the first line of defence they would be caught in the killing ground between the inner and outer walls and have to assault the second wall.


title: Castle

text: Concentric castles were widely copied across Europe, for instance when Edward I of England – who had himself been on Crusade – built castles in Wales in the late 13th century, four of the eight he founded had a concentric design. Not all the features of the Crusader castles from the 13th century were emulated in Europe. For instance, it was common in Crusader castles to have the main gate in the side of a tower and for there to be two turns in the passageway, lengthening the time it took for someone to reach the outer enclosure. It is rare for this bent entrance to be found in Europe.


title: Castle

text: One of the effects of the Livonian Crusade in the Baltic was the introduction of stone and brick fortifications. Although there were hundreds of wooden castles in Prussia and Livonia, the use of bricks and mortar was unknown in the region before the Crusaders. Until the 13th century and start of the 14th centuries, their design was heterogeneous, however this period saw the emergence of a standard plan in the region: a square plan, with four wings around a central courtyard. It was common for castles in the East to have arrowslits in the curtain wall at multiple levels; contemporary builders in Europe were wary of this as they believed it weakened the wall. Arrowslits did not compromise the wall's strength, but it was not until Edward I's programme of castle building that they were widely adopted in Europe.


title: Castle

text: The Crusades also led to the introduction of machicolations into Western architecture. Until the 13th century, the tops of towers had been surrounded by wooden galleries, allowing defenders to drop objects on assailants below. Although machicolations performed the same purpose as the wooden galleries, they were probably an Eastern invention rather than an evolution of the wooden form. Machicolations were used in the East long before the arrival of the Crusaders, and perhaps as early as the first half of the 8th century in Syria.


title: Castle

text: The greatest period of castle building in Spain was in the 11th to 13th centuries, and they were most commonly found in the disputed borders between Christian and Muslim lands. Conflict and interaction between the two groups led to an exchange of architectural ideas, and Spanish Christians adopted the use of detached towers. The Spanish Reconquista, driving the Muslims out of the Iberian Peninsula, was complete in 1492.


title: Castle

text: Although France has been described as "the heartland of medieval architecture", the English were at the forefront of castle architecture in the 12th century. French historian François Gebelin wrote: "The great revival in military architecture was led, as one would naturally expect, by the powerful kings and princes of the time; by the sons of William the Conqueror and their descendants, the Plantagenets, when they became dukes of Normandy. These were the men who built all the most typical twelfth-century fortified castles remaining today". Despite this, by the beginning of the 15th century, the rate of castle construction in England and Wales went into decline. The new castles were generally of a lighter build than earlier structures and presented few innovations, although strong sites were still created such as that of Raglan in Wales. At the same time, French castle architecture came to the fore and led the way in the field of medieval fortifications. Across Europe – particularly the Baltic, Germany, and Scotland – castles were built well into the 16th century.


title: Castle

text: Artillery powered by gunpowder was introduced to Europe in the 1320s and spread quickly. Handguns, which were initially unpredictable and inaccurate weapons, were not recorded until the 1380s. Castles were adapted to allow small artillery pieces – averaging between  – to fire from towers. These guns were too heavy for a man to carry and fire, but if he supported the butt end and rested the muzzle on the edge of the gun port he could fire the weapon. The gun ports developed in this period show a unique feature, that of a horizontal timber across the opening. A hook on the end of the gun could be latched over the timber so the gunner did not have to take the full recoil of the weapon. This adaptation is found across Europe, and although the timber rarely survives, there is an intact example at Castle Doornenburg in the Netherlands. Gunports were keyhole shaped, with a circular hole at the bottom for the weapon and a narrow slit on top to allow the gunner to aim.


title: Castle

text: This form is very common in castles adapted for guns, found in Egypt, Italy, Scotland, and Spain, and elsewhere in between. Other types of port, though less common, were horizontal slits – allowing only lateral movement – and large square openings, which allowed greater movement. The use of guns for defence gave rise to artillery castles, such as that of Château de Ham in France. Defences against guns were not developed until a later stage. Ham is an example of the trend for new castles to dispense with earlier features such as machicolations, tall towers, and crenellations.


title: Castle

text: Bigger guns were developed, and in the 15th century became an alternative to siege engines such as the trebuchet. The benefits of large guns over trebuchets – the most effective siege engine of the Middle Ages before the advent of gunpowder – were those of a greater range and power. In an effort to make them more effective, guns were made ever bigger, although this hampered their ability to reach remote castles. By the 1450s guns were the preferred siege weapon, and their effectiveness was demonstrated by Mehmed II at the Fall of Constantinople.


title: Castle

text: The response towards more effective cannons was to build thicker walls and to prefer round towers, as the curving sides were more likely to deflect a shot than a flat surface. While this sufficed for new castles, pre-existing structures had to find a way to cope with being battered by cannon. An earthen bank could be piled behind a castle's curtain wall to absorb some of the shock of impact.


title: Castle

text: Often, castles constructed before the age of gunpowder were incapable of using guns as their wall-walks were too narrow. A solution to this was to pull down the top of a tower and to fill the lower part with the rubble to provide a surface for the guns to fire from. Lowering the defences in this way had the effect of making them easier to scale with ladders. A more popular alternative defence, which avoided damaging the castle, was to establish bulwarks beyond the castle's defences. These could be built from earth or stone and were used to mount weapons.


title: Castle

text: Around 1500, the innovation of the angled bastion was developed in Italy. With developments such as these, Italy pioneered permanent artillery fortifications, which took over from the defensive role of castles. From this evolved star forts, also known as "trace italienne". The elite responsible for castle construction had to choose between the new type that could withstand cannon fire and the earlier, more elaborate style. The first was ugly and uncomfortable and the latter was less secure, although it did offer greater aesthetic appeal and value as a status symbol. The second choice proved to be more popular as it became apparent that there was little point in trying to make the site genuinely defensible in the face of cannon. For a variety of reasons, not least of which is that many castles have no recorded history, there is no firm number of castles built in the medieval period. However, it has been estimated that between 75,000 and 100,000 were built in western Europe; of these around 1,700 were in England and Wales and around 14,000 in German-speaking areas.


title: Castle

text: Some true castles were built in the Americas by the Spanish and French colonies. The first stage of Spanish fort construction has been termed the "castle period", which lasted from 1492 until the end of the 16th century. Starting with Fortaleza Ozama, "these castles were essentially European medieval castles transposed to America". Among other defensive structures (including forts and citadels), castles were also built in New France towards the end of the 17th century. In Montreal the artillery was not as developed as on the battle-fields of Europe, some of the region's outlying forts were built like the fortified manor houses of France. Fort Longueuil, built from 1695 to 1698 by a baronial family, has been described as "the most medieval-looking fort built in Canada". The manor house and stables were within a fortified bailey, with a tall round turret in each corner. The "most substantial castle-like fort" near Montréal was Fort Senneville, built in 1692 with square towers connected by thick stone walls, as well as a fortified windmill. Stone forts such as these served as defensive residences, as well as imposing structures to prevent Iroquois incursions.


title: Castle

text: Although castle construction faded towards the end of the 16th century, castles did not necessarily all fall out of use. Some retained a role in local administration and became law courts, while others are still handed down in aristocratic families as hereditary seats. A particularly famous example of this is Windsor Castle in England which was founded in the 11th century and is home to the monarch of the United Kingdom. In other cases they still had a role in defence. Tower houses, which are closely related to castles and include pele towers, were defended towers that were permanent residences built in the 14th to 17th centuries. Especially common in Ireland and Scotland, they could be up to five storeys high and succeeded common enclosure castles and were built by a greater social range of people. While unlikely to provide as much protection as a more complex castle, they offered security against raiders and other small threats.


title: Castle

text: According to archaeologists Oliver Creighton and Robert Higham, "the great country houses of the seventeenth to twentieth centuries were, in a social sense, the castles of their day". Though there was a trend for the elite to move from castles into country houses in the 17th century, castles were not completely useless. In later conflicts, such as the English Civil War (1641–1651), many castles were refortified, although subsequently slighted to prevent them from being used again. Some country residences, which were not meant to be fortified, were given a castle appearance to scare away potential invaders such as adding turrets and using small windows. An example of this is the 16th century Bubaqra Castle in Bubaqra, Malta, which was modified in the 18th century.


title: Castle

text: Revival or mock castles became popular as a manifestation of a Romantic interest in the Middle Ages and chivalry, and as part of the broader Gothic Revival in architecture. Examples of these castles include Chapultepec in Mexico, Neuschwanstein in Germany, and Edwin Lutyens' Castle Drogo (1911–1930) – the last flicker of this movement in the British Isles. While churches and cathedrals in a Gothic style could faithfully imitate medieval examples, new country houses built in a "castle style" differed internally from their medieval predecessors. This was because to be faithful to medieval design would have left the houses cold and dark by contemporary standards.


title: Castle

text: Artificial ruins, built to resemble remnants of historic edifices, were also a hallmark of the period. They were usually built as centre pieces in aristocratic planned landscapes. Follies were similar, although they differed from artificial ruins in that they were not part of a planned landscape, but rather seemed to have no reason for being built. Both drew on elements of castle architecture such as castellation and towers, but served no military purpose and were solely for display. A toy castle is used as a common children attraction in playing fields and fun parks, such as the castle of the Playmobil FunPark in Ħal Far, Malta.


title: Castle

text: Once the site of a castle had been selected – whether a strategic position or one intended to dominate the landscape as a mark of power – the building material had to be selected. An earth and timber castle was cheaper and easier to erect than one built from stone. The costs involved in construction are not well-recorded, and most surviving records relate to royal castles. A castle with earthen ramparts, a motte, timber defences and buildings could have been constructed by an unskilled workforce. The source of man-power was probably from the local lordship, and the tenants would already have the necessary skills of felling trees, digging, and working timber necessary for an earth and timber castle. Possibly coerced into working for their lord, the construction of an earth and timber castle would not have been a drain on a client's funds. In terms of time, it has been estimated that an average sized motte – high and wide at the summit – would have taken 50 people about 40 working days. An exceptionally expensive motte and bailey was that of Clones in Ireland, built in 1211 for UK£20. The high cost, relative to other castles of its type, was because labourers had to be imported.


title: Castle

text: The cost of building a castle varied according to factors such as their complexity and transport costs for material. It is certain that stone castles cost a great deal more than those built from earth and timber. Even a very small tower, such as Peveril Castle, would have cost around UK£200. In the middle were castles such as Orford, which was built in the late 12th century for UK£1,400, and at the upper end were those such as Dover, which cost about UK£7,000 between 1181 and 1191. Spending on the scale of the vast castles such as Château Gaillard (an estimated UK£15,000 to UK£20,000 between 1196 and 1198) was easily supported by The Crown, but for lords of smaller areas, castle building was a very serious and costly undertaking. It was usual for a stone castle to take the best part of a decade to finish. The cost of a large castle built over this time (anywhere from UK£1,000 to UK£10,000) would take the income from several manors, severely impacting a lord's finances. Costs in the late 13th century were of a similar order, with castles such as Beaumaris and Rhuddlan costing UK£14,500 and UK£9,000 respectively. Edward I's campaign of castle-building in Wales cost UK£80,000 between 1277 and 1304, and UK£95,000 between 1277 and 1329. Renowned designer Master James of Saint George, responsible for the construction of Beaumaris, explained the cost:


title: Castle

text: Not only were stone castles expensive to build in the first place, but their maintenance was a constant drain. They contained a lot of timber, which was often unseasoned and as a result needed careful upkeep. For example, it is documented that in the late 12th century repairs at castles such as Exeter and Gloucester cost between UK£20 and UK£50 annually.


title: Castle

text: Medieval machines and inventions, such as the treadwheel crane, became indispensable during construction, and techniques of building wooden scaffolding were improved upon from Antiquity. When building in stone a prominent concern of medieval builders was to have quarries close at hand. There are examples of some castles where stone was quarried on site, such as Chinon, Château de Coucy and Château Gaillard. When it was built in 992 in France the stone tower at Château de Langeais was high, wide, and long with walls averaging . The walls contain of stone and have a total surface (both inside and out) of . The tower is estimated to have taken 83,000 average working days to complete, most of which was unskilled labour.


title: Castle

text: Many countries had both timber and stone castles, however Denmark had few quarries and as a result most of its castles are earth and timber affairs, or later on built from brick. Brick-built structures were not necessarily weaker than their stone-built counterparts. Brick castles are less common in England than stone or earth and timber constructions, and often it was chosen for its aesthetic appeal or because it was fashionable, encouraged by the brick architecture of the Low Countries. For example, when Tattershall Castle in England was built between 1430 and 1450, there was plenty of stone available nearby, but the owner, Lord Cromwell, chose to use brick. About 700,000 bricks were used to build the castle, which has been described as "the finest piece of medieval brick-work in England". Most Spanish castles were built from stone, whereas castles in Eastern Europe were usually of timber construction.


title: Castle

text: "On the Construction of the Castle of Safed", written in the early 1260s, describes the construction of a new castle at Safed. It is "one of the fullest" medieval accounts of a castle's construction.


title: Castle

text: Due to the lord's presence in a castle, it was a centre of administration from where he controlled his lands. He relied on the support of those below him, as without the support of his more powerful tenants a lord could expect his power to be undermined. Successful lords regularly held court with those immediately below them on the social scale, but absentees could expect to find their influence weakened. Larger lordships could be vast, and it would be impractical for a lord to visit all his properties regularly, so deputies were appointed. This especially applied to royalty, who sometimes owned land in different countries.


title: Castle

text: To allow the lord to concentrate on his duties regarding administration, he had a household of servants to take care of chores such as providing food. The household was run by a chamberlain, while a treasurer took care of the estate's written records. Royal households took essentially the same form as baronial households, although on a much larger scale and the positions were more prestigious. An important role of the household servants was the preparation of food; the castle kitchens would have been a busy place when the castle was occupied, called on to provide large meals. Without the presence of a lord's household, usually because he was staying elsewhere, a castle would have been a quiet place with few residents, focused on maintaining the castle.


title: Castle

text: As social centres castles were important places for display. Builders took the opportunity to draw on symbolism, through the use of motifs, to evoke a sense of chivalry that was aspired to in the Middle Ages amongst the elite. Later structures of the Romantic Revival would draw on elements of castle architecture such as battlements for the same purpose. Castles have been compared with cathedrals as objects of architectural pride, and some castles incorporated gardens as ornamental features. The right to crenellate, when granted by a monarch – though it was not always necessary – was important not just as it allowed a lord to defend his property but because crenellations and other accoutrements associated with castles were prestigious through their use by the elite. Licences to crenellate were also proof of a relationship with or favour from the monarch, who was the one responsible for granting permission.


title: Castle

text: Courtly love was the eroticisation of love between the nobility. Emphasis was placed on restraint between lovers. Though sometimes expressed through chivalric events such as tournaments, where knights would fight wearing a token from their lady, it could also be private and conducted in secret. The legend of Tristan and Iseult is one example of stories of courtly love told in the Middle Ages. It was an ideal of love between two people not married to each other, although the man might be married to someone else. It was not uncommon or ignoble for a lord to be adulterous – Henry I of England had over 20 bastards for instance – but for a lady to be promiscuous was seen as dishonourable.


title: Castle

text: The purpose of marriage between the medieval elites was to secure land. Girls were married in their teens, but boys did not marry until they came of age. There is a popular conception that women played a peripheral role in the medieval castle household, and that it was dominated by the lord himself. This derives from the image of the castle as a martial institution, but most castles in England, France, Ireland, and Scotland were never involved in conflicts or sieges, so the domestic life is a neglected facet. The lady was given a dower of her husband's estates – usually about a third – which was hers for life, and her husband would inherit on her death. It was her duty to administer them directly, as the lord administered his own land. Despite generally being excluded from military service, a woman could be in charge of a castle, either on behalf of her husband or if she was widowed. Because of their influence within the medieval household, women influenced construction and design, sometimes through direct patronage; historian Charles Coulson emphasises the role of women in applying "a refined aristocratic taste" to castles due to their long term residence.


title: Castle

text: The positioning of castles was influenced by the available terrain. Whereas hill castles such as Marksburg were common in Germany, where 66 per cent of all known medieval were highland area while 34 per cent were on low-lying land, they formed a minority of sites in England. Because of the range of functions they had to fulfil, castles were built in a variety of locations. Multiple factors were considered when choosing a site, balancing between the need for a defendable position with other considerations such as proximity to resources. For instance many castles are located near Roman roads, which remained important transport routes in the Middle Ages, or could lead to the alteration or creation of new road systems in the area. Where available it was common to exploit pre-existing defences such as building with a Roman fort or the ramparts of an Iron Age hillfort. A prominent site that overlooked the surrounding area and offered some natural defences may also have been chosen because its visibility made it a symbol of power. Urban castles were particularly important in controlling centres of population and production, especially with an invading force, for instance in the aftermath of the Norman Conquest of England in the 11th century the majority of royal castles were built in or near towns.


title: Castle

text: As castles were not simply military buildings but centres of administration and symbols of power, they had a significant impact on the surrounding landscape. Placed by a frequently-used road or river, the toll castle ensured that a lord would get his due toll money from merchants. Rural castles were often associated with mills and field systems due to their role in managing the lord's estate, which gave them greater influence over resources. Others were adjacent to or in royal forests or deer parks and were important in their upkeep. Fish ponds were a luxury of the lordly elite, and many were found next to castles. Not only were they practical in that they ensured a water supply and fresh fish, but they were a status symbol as they were expensive to build and maintain.


title: Castle

text: Although sometimes the construction of a castle led to the destruction of a village, such as at Eaton Socon in England, it was more common for the villages nearby to have grown as a result of the presence of a castle. Sometimes planned towns or villages were created around a castle. The benefits of castle building on settlements was not confined to Europe. When the 13th-century Safad Castle was founded in Galilee in the Holy Land, the 260 villages benefitted from the inhabitants' newfound ability to move freely. When built, a castle could result in the restructuring of the local landscape, with roads moved for the convenience of the lord. Settlements could also grow naturally around a castle, rather than being planned, due to the benefits of proximity to an economic centre in a rural landscape and the safety given by the defences. Not all such settlements survived, as once the castle lost its importance – perhaps succeeded by a manor house as the centre of administration – the benefits of living next to a castle vanished and the settlement depopulated.


title: Castle

text: During and shortly after the Norman Conquest of England, castles were inserted into important pre-existing towns to control and subdue the populace. They were usually located near any existing town defences, such as Roman walls, although this sometimes resulted in the demolition of structures occupying the desired site. In Lincoln, 166 houses were destroyed to clear space for the castle, and in York agricultural land was flooded to create a moat for the castle. As the military importance of urban castles waned from their early origins, they became more important as centres of administration, and their financial and judicial roles. When the Normans invaded Ireland, Scotland, and Wales in the 11th and 12th centuries, settlement in those countries was predominantly non-urban, and the foundation of towns was often linked with the creation of a castle.


title: Castle

text: The location of castles in relation to high status features, such as fish ponds, was a statement of power and control of resources. Also often found near a castle, sometimes within its defences, was the parish church. This signified a close relationship between feudal lords and the Church, one of the most important institutions of medieval society. Even elements of castle architecture that have usually been interpreted as military could be used for display. The water features of Kenilworth Castle in England – comprising a moat and several satellite ponds – forced anyone approaching a water castle entrance to take a very indirect route, walking around the defences before the final approach towards the gateway. Another example is that of the 14th-century Bodiam Castle, also in England; although it appears to be a state of the art, advanced castle it is in a site of little strategic importance, and the moat was shallow and more likely intended to make the site appear impressive than as a defence against mining. The approach was long and took the viewer around the castle, ensuring they got a good look before entering. Moreover, the gunports were impractical and unlikely to have been effective.


title: Castle

text: As a static structure, castles could often be avoided. Their immediate area of influence was about and their weapons had a short range even early in the age of artillery. However, leaving an enemy behind would allow them to interfere with communications and make raids. Garrisons were expensive and as a result often small unless the castle was important. Cost also meant that in peacetime garrisons were smaller, and small castles were manned by perhaps a couple of watchmen and gate-guards. Even in war, garrisons were not necessarily large as too many people in a defending force would strain supplies and impair the castle's ability to withstand a long siege. In 1403, a force of 37 archers successfully defended Caernarfon Castle against two assaults by Owain Glyndŵr's allies during a long siege, demonstrating that a small force could be effective.


title: Castle

text: Early on, manning a castle was a feudal duty of vassals to their magnates, and magnates to their kings, however this was later replaced with paid forces. A garrison was usually commanded by a constable whose peacetime role would have been looking after the castle in the owner's absence. Under him would have been knights who by benefit of their military training would have acted as a type of officer class. Below them were archers and bowmen, whose role was to prevent the enemy reaching the walls as can be seen by the positioning of arrowslits.


title: Castle

text: If it was necessary to seize control of a castle an army could either launch an assault or lay siege. It was more efficient to starve the garrison out than to assault it, particularly for the most heavily defended sites. Without relief from an external source, the defenders would eventually submit. Sieges could last weeks, months, and in rare cases years if the supplies of food and water were plentiful. A long siege could slow down the army, allowing help to come or for the enemy to prepare a larger force for later. Such an approach was not confined to castles, but was also applied to the fortified towns of the day. On occasion, siege castles would be built to defend the besiegers from a sudden sally and would have been abandoned after the siege ended one way or another.


title: Castle

text: If forced to assault a castle, there were many options available to the attackers. For wooden structures, such as early motte-and-baileys, fire was a real threat and attempts would be made to set them alight as can be seen in the Bayeux Tapestry. Projectile weapons had been used since antiquity and the mangonel and petraria – from Eastern and Roman origins respectively – were the main two that were used into the Middle Ages. The trebuchet, which probably evolved from the petraria in the 13th century, was the most effective siege weapon before the development of cannons. These weapons were vulnerable to fire from the castle as they had a short range and were large machines. Conversely, weapons such as trebuchets could be fired from within the castle due to the high trajectory of its projectile, and would be protected from direct fire by the curtain walls.


title: Castle

text: Ballistas or springalds were siege engines that worked on the same principles as crossbows. With their origins in Ancient Greece, tension was used to project a bolt or javelin. Missiles fired from these engines had a lower trajectory than trebuchets or mangonels and were more accurate. They were more commonly used against the garrison rather than the buildings of a castle. Eventually cannons developed to the point where they were more powerful and had a greater range than the trebuchet, and became the main weapon in siege warfare.


title: Castle

text: Walls could be undermined by a sap. A mine leading to the wall would be dug and once the target had been reached, the wooden supports preventing the tunnel from collapsing would be burned. It would cave in and bring down the structure above. Building a castle on a rock outcrop or surrounding it with a wide, deep moat helped prevent this. A counter-mine could be dug towards the besiegers' tunnel; assuming the two converged, this would result in underground hand-to-hand combat. Mining was so effective that during the siege of Margat in 1285 when the garrison were informed a sap was being dug they surrendered. Battering rams were also used, usually in the form of a tree trunk given an iron cap. They were used to force open the castle gates, although they were sometimes used against walls with less effect.


title: Castle

text: As an alternative to the time-consuming task of creating a breach, an escalade could be attempted to capture the walls with fighting along the walkways behind the battlements. In this instance, attackers would be vulnerable to arrowfire. A safer option for those assaulting a castle was to use a siege tower, sometimes called a belfry. Once ditches around a castle were partially filled in, these wooden, movable towers could be pushed against the curtain wall. As well as offering some protection for those inside, a siege tower could overlook the interior of a castle, giving bowmen an advantageous position from which to unleash missiles.


title: Work (physics)

text: In physics, work is the energy transferred to or from an object via the application of force along a displacement. In its simplest form, for a constant force aligned with the direction of motion, the work equals the product of the force strength and the distance traveled. A force is said to do "positive work" if when applied it has a component in the direction of the displacement of the point of application. A force does "negative work" if it has a component opposite to the direction of the displacement at the point of application of the force.


title: Work (physics)

text: For example, when a ball is held above the ground and then dropped, the work done by the gravitational force on the ball as it falls is positive, and is equal to the weight of the ball (a force) multiplied by the distance to the ground (a displacement). If the ball is thrown upwards, the work done by its weight is negative, and is equal to the weight multiplied by the displacement in the upwards direction.


title: Work (physics)

text: When the force is constant and the angle between the force and the displacement is , then the work done is given by:


title: Work (physics)

text: Work is a scalar quantity, so it has only magnitude and no direction. Work transfers energy from one place to another, or one form to another. The SI unit of work is the joule (J), the same unit as for energy.


title: Work (physics)

text: The ancient Greek understanding of physics was limited to the statics of simple machines (the balance of forces), and did not include dynamics or the concept of work. During the Renaissance the dynamics of the "Mechanical Powers", as the simple machines were called, began to be studied from the standpoint of how far they could lift a load, in addition to the force they could apply, leading eventually to the new concept of mechanical work. The complete dynamic theory of simple machines was worked out by Italian scientist Galileo Galilei in 1600 in "Le Meccaniche" ("On Mechanics"), in which he showed the underlying mathematical similarity of the machines as force amplifiers. He was the first to explain that simple machines do not create energy, only transform it.


title: Work (physics)

text: According to the 1957 physics textbook by Max Jammer, the term "work" was introduced in 1826 by the French mathematician Gaspard-Gustave Coriolis as "weight "lifted" through a height", which is based on the use of early steam engines to lift buckets of water out of flooded ore mines. According to Rene Dugas, French engineer and historian, it is to Solomon of Caux "that we owe the term "work" in the sense that it is used in mechanics now".


title: Work (physics)

text: Although "work" was not formally used until 1826, similar concepts existed before then. In 1759, John Smeaton described a quantity that he called "power" "to signify the exertion of strength, gravitation, impulse, or pressure, as to produce motion." Smeaton continues that this quantity can be calculated if "the weight raised is multiplied by the height to which it can be raised in a given time," making this definition remarkably similar to Coriolis'.


title: Work (physics)

text: The SI unit of work is the joule (J), named after the 19th-century English physicist James Prescott Joule, which is defined as the work required to exert a force of one newton through a displacement of one metre.


title: Work (physics)

text: The dimensionally equivalent newton-metre (N⋅m) is sometimes used as the measuring unit for work, but this can be confused with the measurement unit of torque. Usage of N⋅m is discouraged by the SI authority, since it can lead to confusion as to whether the quantity expressed in newton-metres is a torque measurement, or a measurement of work.


title: Work (physics)

text: Non-SI units of work include the newton-metre, erg, the foot-pound, the foot-poundal, the kilowatt hour, the litre-atmosphere, and the horsepower-hour. Due to work having the same physical dimension as heat, occasionally measurement units typically reserved for heat or energy content, such as therm, BTU and calorie, are used as a measuring unit.


title: Work (physics)

text: The work done by a constant force of magnitude on a point that moves a displacement in a straight line in the direction of the force is the product


title: Work (physics)

text: For example, if a force of 10 newtons () acts along a point that travels 2 metres (), then . This is approximately the work done lifting a 1 kg object from ground level to over a person's head against the force of gravity.


title: Work (physics)

text: The work is doubled either by lifting twice the weight the same distance or by lifting the same weight twice the distance.


title: Work (physics)

text: Work is closely related to energy. The work–energy principle states that an increase in the kinetic energy of a rigid body is caused by an equal amount of positive work done on the body by the resultant force acting on that body. Conversely, a decrease in kinetic energy is caused by an equal amount of negative work done by the resultant force. Thus, if the net work is positive, then the particle’s kinetic energy increases by the amount of the work. If the net work done is negative, then the particle’s kinetic energy decreases by the amount of work.


title: Work (physics)

text: From Newton's second law, it can be shown that work on a free (no fields), rigid (no internal degrees of freedom) body, is equal to the change in kinetic energy corresponding to the linear velocity and angular velocity of that body,


title: Work (physics)

text: The work of forces generated by a potential function is known as potential energy and the forces are said to be conservative. Therefore, work on an object that is merely displaced in a conservative force field, without change in velocity or rotation, is equal to "minus" the change of potential energy of the object,


title: Work (physics)

text: These formulas show that work is the energy associated with the action of a force, so work subsequently possesses the physical dimensions, and units, of energy.


title: Work (physics)

text: Constraint forces determine the object's displacement in the system, limiting it within a range. For example, in the case of a slope plus gravity, the object is "stuck to" the slope and, when attached to a taut string, it cannot move in an outwards direction to make the string any 'tauter'. It eliminates all displacements in that direction, that is, the velocity in the direction of the constraint is limited to 0, so that the constraint forces do not perform work on the system.


title: Work (physics)

text: For a mechanical system, constraint forces eliminate movement in directions that characterize the constraint. Thus the virtual work done by the forces of constraint is zero, a result which is only true if friction forces are excluded.


title: Work (physics)

text: Fixed, frictionless constraint forces do not perform work on the system, as the angle between the motion and the constraint forces is always 90°. Examples of workless constraints are: rigid interconnections between particles, sliding motion on a frictionless surface, and rolling contact without slipping.


title: Work (physics)

text: For example, in a pulley system like the Atwood machine, the internal forces on the rope and at the supporting pulley do no work on the system. Therefore, work need only be computed for the gravitational forces acting on the bodies. Another example is the centripetal force exerted "inwards" by a string on a ball in uniform circular motion "sideways" constrains the ball to circular motion restricting its movement away from the centre of the circle. This force does zero work because it is perpendicular to the velocity of the ball.


title: Work (physics)

text: The magnetic force on a charged particle is , where is the charge, is the velocity of the particle, and is the magnetic field. The result of a cross product is always perpendicular to both of the original vectors, so . The dot product of two perpendicular vectors is always zero, so the work , and the magnetic force does not do work. It can change the direction of motion but never change the speed.


title: Work (physics)

text: For moving objects, the quantity of work/time (power) is integrated along the trajectory of the point of application of the force. Thus, at any instant, the rate of the work done by a force (measured in joules/second, or watts) is the scalar product of the force (a vector), and the velocity vector of the point of application. This scalar product of force and velocity is known as instantaneous power. Just as velocities may be integrated over time to obtain a total distance, by the fundamental theorem of calculus, the total work along a path is similarly the time-integral of instantaneous power applied along the trajectory of the point of application.


title: Work (physics)

text: Work is the result of a force on a point that follows a curve , with a velocity , at each instant. The small amount of work that occurs over an instant of time is calculated as


title: Work (physics)

text: where the is the power over the instant . The sum of these small amounts of work over the trajectory of the point yields the work,


title: Work (physics)

text: where "C" is the trajectory from x("t") to x("t"). This integral is computed along the trajectory of the particle, and is therefore said to be "path dependent".


title: Work (physics)

text: If the force is always directed along this line, and the magnitude of the force is , then this integral simplifies to


title: Work (physics)

text: where is displacement along the line. If is constant, in addition to being directed along the line, then the integral simplifies further to


title: Work (physics)

text: This calculation can be generalized for a constant force that is not directed along the line, followed by the particle. In this case the dot product , where is the angle between the force vector and the direction of movement, that is


title: Work (physics)

text: When a force component is perpendicular to the displacement of the object (such as when a body moves in a circular path under a central force), no work is done, since the cosine of 90° is zero. Thus, no work can be performed by gravity on a planet with a circular orbit (this is ideal, as all orbits are slightly elliptical). Also, no work is done on a body moving circularly at a constant speed while constrained by mechanical force, such as moving at constant speed in a frictionless ideal centrifuge.


title: Work (physics)

text: Calculating the work as "force times straight path segment" would only apply in the most simple of circumstances, as noted above. If force is changing, or if the body is moving along a curved path, possibly rotating and not necessarily rigid, then only the path of the application point of the force is relevant for the work done, and only the component of the force parallel to the application point velocity is doing work (positive work when in the same direction, and negative when in the opposite direction of the velocity). This component of force can be described by the scalar quantity called "scalar tangential component" (, where is the angle between the force and the velocity). And then the most general definition of work can be formulated as follows:


title: Work (physics)

text: A force couple results from equal and opposite forces, acting on two different points of a rigid body. The sum (resultant) of these forces may cancel, but their effect on the body is the couple or torque T. The work of the torque is calculated as


title: Work (physics)

text: where the is the power over the instant . The sum of these small amounts of work over the trajectory of the rigid body yields the work,


title: Work (physics)

text: This integral is computed along the trajectory of the rigid body with an angular velocity that varies with time, and is therefore said to be "path dependent".


title: Work (physics)

text: where formula_13 is the angle of rotation about the constant unit vector . In this case, the work of the torque becomes,


title: Work (physics)

text: where is the trajectory from formula_15 to formula_16. This integral depends on the rotational trajectory formula_17, and is therefore path-dependent.


title: Work (physics)

text: This result can be understood more simply by considering the torque as arising from a force of constant magnitude , being applied perpendicularly to a lever arm at a distance formula_21, as shown in the figure. This force will act through the distance along the circular arc formula_22, so the work done is


title: Work (physics)

text: Notice that only the component of torque in the direction of the angular velocity vector contributes to the work.


title: Work (physics)

text: The scalar product of a force and the velocity of its point of application defines the power input to a system at an instant of time. Integration of this power over the trajectory of the point of application, , defines the work input to the system by the force.


title: Work (physics)

text: Therefore, the work done by a force on an object that travels along a curve is given by the line integral:


title: Work (physics)

text: In general this integral requires that the path along which the velocity is defined, so the evaluation of work is said to be path dependent.


title: Work (physics)

text: If the work for an applied force is independent of the path, then the work done by the force, by the gradient theorem, defines a potential function which is evaluated at the start and end of the trajectory of the point of application. This means that there is a potential function , that can be evaluated at the two points and to obtain the work over any trajectory between these two points. It is tradition to define this function with a negative sign so that positive work is a reduction in the potential, that is


title: Work (physics)

text: The function is called the potential energy associated with the applied force. The force derived from such a potential function is said to be conservative. Examples of forces that have potential energies are gravity and spring forces.


title: Work (physics)

text: Because the potential defines a force at every point in space, the set of forces is called a force field. The power applied to a body by a force field is obtained from the gradient of the work, or potential, in the direction of the velocity of the body, that is


title: Work (physics)

text: In the absence of other forces, gravity results in a constant downward acceleration of every freely moving object. Near Earth's surface the acceleration due to gravity is and the gravitational force on an object of mass "m" is . It is convenient to imagine this gravitational force concentrated at the center of mass of the object.


title: Work (physics)

text: If an object with weight is displaced upwards or downwards a vertical distance , the work done on the object is:


title: Work (physics)

text: where "F" is weight (pounds in imperial units, and newtons in SI units), and Δ"y" is the change in height "y". Notice that the work done by gravity depends only on the vertical movement of the object. The presence of friction does not affect the work done on the object by its weight.


title: Work (physics)

text: Let the mass move at the velocity ; then the work of gravity on this mass as it moves from position to is given by


title: Work (physics)

text: where and are the radial and tangential unit vectors directed relative to the vector from to , and we use the fact that formula_34 Use this to simplify the formula for work of gravity to,


title: Work (physics)

text: is the gravitational potential function, also known as gravitational potential energy. The negative sign follows the convention that work is gained from a loss of potential energy.


title: Work (physics)

text: Consider a spring that exerts a horizontal force that is proportional to its deflection in the "x" direction independent of how a body moves. The work of this spring on a body moving along the space with the curve , is calculated using its velocity, , to obtain


title: Work (physics)

text: For convenience, consider contact with the spring occurs at , then the integral of the product of the distance and the x-velocity, , over time is . The work is the product of the distance times the spring force, which is also dependent on distance; hence the result.


title: Work (physics)

text: The principle of work and kinetic energy (also known as the work–energy principle) states that "the work done by all forces acting on a particle (the work of the resultant force) equals the change in the kinetic energy of the particle." That is, the work "W" done by the resultant force on a particle equals the change in the particle's kinetic energy formula_41,


title: Work (physics)

text: where formula_43 and formula_44 are the speeds of the particle before and after the work is done, and is its mass.


title: Work (physics)

text: The derivation of the "work–energy principle" begins with Newton’s second law of motion and the resultant force on a particle. Computation of the scalar product of the forces with the velocity of the particle evaluates the instantaneous power added to the system.


title: Work (physics)

text: Constraints define the direction of movement of the particle by ensuring there is no component of velocity in the direction of the constraint force. This also means the constraint forces do not add to the instantaneous power. The time integral of this scalar equation yields work from the instantaneous power, and kinetic energy from the scalar product of velocity and acceleration. The fact that the work–energy principle eliminates the constraint forces underlies Lagrangian mechanics.


title: Work (physics)

text: This section focuses on the work–energy principle as it applies to particle dynamics. In more general systems work can change the potential energy of a mechanical device, the thermal energy in a thermal system, or the electrical energy in an electrical device. Work transfers energy from one place to another or one form to another.


title: Work (physics)

text: In the case the resultant force is constant in both magnitude and direction, and parallel to the velocity of the particle, the particle is moving with constant acceleration "a" along a straight line. The relation between the net force and the acceleration is given by the equation (Newton's second law), and the particle displacement can be expressed by the equation


title: Work (physics)

text: The work of the net force is calculated as the product of its magnitude and the particle displacement. Substituting the above equations, one obtains:


title: Work (physics)

text: In the general case of rectilinear motion, when the net force is not constant in magnitude, but is constant in direction, and parallel to the velocity of the particle, the work must be integrated along the path of the particle:


title: Work (physics)

text: For any net force acting on a particle moving along any curvilinear path, it can be demonstrated that its work equals the change in the kinetic energy of the particle by a simple derivation analogous to the equation above. It is known as the work–energy principle:


title: Work (physics)

text: The remaining part of the above derivation is just simple calculus, same as in the preceding rectilinear case.


title: Work (physics)

text: In particle dynamics, a formula equating work applied to a system to its change in kinetic energy is obtained as a first integral of Newton's second law of motion. It is useful to notice that the resultant force used in Newton's laws can be separated into forces that are applied to the particle and forces imposed by constraints on the movement of the particle. Remarkably, the work of a constraint force is zero, therefore only the work of the applied forces need be considered in the work–energy principle.


title: Work (physics)

text: To see this, consider a particle P that follows the trajectory with a force acting on it. Isolate the particle from its environment to expose constraint forces , then Newton's Law takes the form


title: Work (physics)

text: because the constraint forces are perpendicular to the particle velocity. Integrate this equation along its trajectory from the point to the point to obtain


title: Work (physics)

text: The left side of this equation is the work of the applied force as it acts on the particle along the trajectory from time to time . This can also be written as


title: Work (physics)

text: The right side of the first integral of Newton's equations can be simplified using the following identity


title: Work (physics)

text: (see product rule for derivation). Now it is integrated explicitly to obtain the change in kinetic energy,


title: Work (physics)

text: It is useful to resolve the velocity and acceleration vectors into tangential and normal components along the trajectory , such that


title: Work (physics)

text: Consider the case of a vehicle moving along a straight horizontal trajectory under the action of a driving force and gravity that sum to . The constraint forces between the vehicle and the road define , and we have


title: Work (physics)

text: For convenience let the trajectory be along the X-axis, so and the velocity is , then , and , where "F" is the component of F along the X-axis, so


title: Work (physics)

text: As an example consider a car skidding to a stop, where "k" is the coefficient of friction and "W" is the weight of the car. Then the force along the trajectory is . The velocity "v" of the car can be determined from the length of the skid using the work–energy principle,


title: Work (physics)

text: Consider the case of a vehicle that starts at rest and coasts down an inclined surface (such as mountain road), the work–energy principle helps compute the minimum distance that the vehicle travels to reach a velocity , of say 60 mph (88 fps). Rolling resistance and air drag will slow the vehicle down so the actual distance will be greater than if these forces are neglected.


title: Work (physics)

text: Let the trajectory of the vehicle following the road be which is a curve in three-dimensional space. The force acting on the vehicle that pushes it down the road is the constant force of gravity , while the force of the road on the vehicle is the constraint force . Newton's second law yields,


title: Work (physics)

text: where is the magnitude of . The constraint forces between the vehicle and the road cancel from this equation because , which means they do no work.


title: Work (physics)

text: The weight force "W" is constant along the trajectory and the integral of the vertical velocity is the vertical distance, therefore,


title: Work (physics)

text: Recall that V("t")=0. Notice that this result does not depend on the shape of the road followed by the vehicle.


title: Work (physics)

text: In order to determine the distance along the road assume the downgrade is 6%, which is a steep road. This means the altitude decreases 6 feet for every 100 feet traveled—for angles this small the sin and tan functions are approximately equal. Therefore, the distance in feet down a 6% grade to reach the velocity is at least


title: Work (physics)

text: The work of forces acting at various points on a single rigid body can be calculated from the work of a resultant force and torque. To see this, let the forces F, F, ..., F act on the points X, X, ..., X in a rigid body.


title: Work (physics)

text: The trajectories of X, "i" = 1, ..., "n" are defined by the movement of the rigid body. This movement is given by the set of rotations ["A"("t")] and the trajectory d("t") of a reference point in the body. Let the coordinates x "i" = 1, ..., "n" define these points in the moving rigid body's reference frame "M", so that the trajectories traced in the fixed frame "F" are given by


title: Work (physics)

text: The small amount of work by the forces over the small displacements can be determined by approximating the displacement by so


title: Work (physics)

text: where F and T are the resultant force and torque applied at the reference point d of the moving frame "M" in the rigid body.


title: Mercedes-Benz E-Class (W211)

text: The Mercedes-Benz W211 is the third generation Mercedes-Benz E-Class made from 2002 to 2009 in sedan/saloon and station wagon/estate configurations – replacing the W210 E-Class models and superseded by the Mercedes-Benz W212 in 2009.


title: Mercedes-Benz E-Class (W211)

text: Launched in 2002 for the 2003 model year, the W211 E-Class was another evolution of the previous model. Before North American sales began, the car was shown in the 2002 movie "Men in Black II". The W211 development program began in 1997, followed by design work. The final designs were chosen in 1999 and German patents were later filed on December 18, 2000 utilizing an E 500 prototype. Development ended in 2001 after 48 months, at a total cost of €2 billion. Pilot production went into testing in the summer of 2001, the W211 E-Class debut at the Brussels Motor Show in January 2002.


title: Mercedes-Benz E-Class (W211)

text: The W211 Platform was also the base foundation for which the newly re-introduced Chrysler LX cars were engineered from (Chrysler 300, Dodge Charger, Dodge Magnum).


title: Mercedes-Benz E-Class (W211)

text: at the 2002 European Motor Show Brussels featuring twin-headlights, angled slightly rearward. The 2003 E-Class was larger than its predecessors while offering less interior space, particularly in the estate version, than the W210 it replaced. It offered gasoline or diesel engines with a choice of rear or 4-wheel drive.


title: Mercedes-Benz E-Class (W211)

text: Mercedes-Benz claimed to have reduced the fuel consumption of the new E-Class by up to 0.9 litres per 100 km compared with the outgoing model. The redesigned 2003 model featured electrohydraulic braking system marketed as "Sensotronic Brake Control" (SBC), which was standard equipment in the E-Class. Options included multicontour front seats and dual control air suspension system marketed as "Airmatic DC".


title: Mercedes-Benz E-Class (W211)

text: Air suspension was standard equipment in the top-of-the-range E 500 V8 model and was available as an option on all other E-Class models. The W211 is a more complex car than its predecessor with a programmable serial bus and many automated systems.


title: Mercedes-Benz E-Class (W211)

text: The 2003 E-Class was offered in sedan and 5-door station wagon configurations in three trim lines, marketed as Classic, Elegance and Avantgarde. The W211 was the first E-Class since 1985 equipped with two windshield wipers.


title: Mercedes-Benz E-Class (W211)

text: The transmission options were 5 or 7-speed automatic or 6-speed manual. V6, V8, inline-4 and supercharged inline-4 engines were offered. Engine outputs of E 240 and E 270 models from the previous W210 E-Class were given a 5 kW increase to 130 kW, while the E 500 uses the 225 kW 5.0-litre V8 from the W220 S-Class to supersede the W210 E 430. The E 320 remained unchanged, producing 165 kW of power.


title: Mercedes-Benz E-Class (W211)

text: The E 320 CDI used the in-line 6-cylinder diesel engine, OM648, that made at 4,200 rpm and at 1,800–2,600 rpm.


title: Mercedes-Benz E-Class (W211)

text: Engines were updated in as a part of the facelift and the new 320 CDI was powered by a 2987 cc OM642 V6 engine delivering 224 hp at 3,800 rpm and at 1,600–2,800 rpm.


title: Mercedes-Benz E-Class (W211)

text: The E 400 CDI used Mercedes-Benz's OM628 V8 diesel engine, that made at 4,000 rpm and at 1,700–2,600 rpm.


title: Mercedes-Benz E-Class (W211)

text: The second generation E 55 AMG debuted in September 2002 at the Paris Motor Show. It debuted as the fastest production sedan in the world. The E 55 AMG was also offered in an estate version for later model years.


title: Mercedes-Benz E-Class (W211)

text: The E 55 AMG is powered by the M113K engine, a 5.4 L V8 with a Lysholm type supercharger manufactured by IHI. The E 55's engine won International Performance Engine of the Year for 2003. The E 55's engine, although the same as the one in the SL55 AMG, had less horsepower, at and of torque. The difference in power is due to a smaller-diameter, longer-length exhaust system in the E 55.


title: Mercedes-Benz E-Class (W211)

text: The supercharged 5.4 L V8 engine was mated to the Speedshift 5-speed automatic transmission, which has a torque capacity of , as the newer 7G-Tronic introduced in 2003 is limited to , not enough to handle the torque from the supercharged V8.


title: Mercedes-Benz E-Class (W211)

text: E 55 came with an AMG tuned Airmatic suspension with 3 different driving modes as well as the ability to significantly raise the car. The E 55 features cross drilled disc brakes at the front with 8 piston calipers. The rear brakes consist of inch discs and 4 piston calipers. The E 55 came with 245/40/18 tires up front and 265/35/18 in the rear with performance tires on the standard AMG 18" split spoke wheels.


title: Mercedes-Benz E-Class (W211)

text: "Car and Driver" reported in their testing that the E 55 AMG was faster than the SL55 AMG. The E 55 AMG was the fastest four door car in Mercedes-Benz's lineup at the time, and easily outperformed its rivals. While the E 55 could accelerate from 0- in 9.8 seconds, it took the Audi RS6 11 seconds. The E 55 was the fastest production sedan available until Mercedes-Benz released the S65 AMG. However, "Car and Driver" criticized the brakes on the E 55, chastising them for being difficult to modulate, and said that the car as a whole felt 'aloof'.


title: Mercedes-Benz E-Class (W211)

text: "Car and Driver" also tested an E 55 AMG Wagon, which weighs more than the sedan. They found that it accelerated from in 4.1 seconds and in 9.7 seconds.


title: Mercedes-Benz E-Class (W211)

text: The W211 was updated in 2006 for the 2007 model year. There was new standard and optional equipment, which enabled the W211 to hold its own against its competitors. Sensotronic was dropped due to customer complaints about its software, while Pre-Safe (w/o autonomous braking) was made standard. The announced vehicle was unveiled at the 2006 New York International Auto Show. In total, 29 model variants were available, with 16 Saloons and 13 Estates. New standard equipment included PRE-SAFE active protection, NECK-PRO head restraints, flashing brake lights, tyre pressure monitor. The optional Intelligent Light System included bi-xenon headlamps and 5 different lighting functions. The bodies were restyled including the front grill, rear view mirror, side mirrors, redesigned headlamps, front spoiler, rear lights, gear knob and steering wheel.


title: Mercedes-Benz E-Class (W211)

text: Coinciding with the minor model update, the largest factory built engine in the E-class range, the E 500 (badged E 550 in some countries), had its engine size increased from 5 litres to 5.5 litres in 2006.


title: Mercedes-Benz E-Class (W211)

text: The E 63 AMG was the refreshed high-performance model of the W211, replacing the E 55 AMG. Besides the Saloon, it was also offered in the Estate body style similarly to the E 55 AMG estate model to compete with the new wagon versions of the BMW M5 (E61) and Audi RS 6 (C6), though those two high-performance wagons were never sold in North America.


title: Mercedes-Benz E-Class (W211)

text: This engine had a high-pressure die-cast alloy cylinder block with twin-wire arc spray coated running surfaces. Compression ratio is 11.3:1. According to many auto journalists, the E 63 AMG was one of the quickest production sports sedans in the world. Both the sedan (saloon) and wagon had a 0– acceleration time of 4.3 seconds. Compared to the previous E 55 AMG, the E 63 AMG had more horsepower but less torque, enabling it to be mated to the newer 7G-Tronic automatic transmission.


title: Mercedes-Benz E-Class (W211)

text: While the E 500 and E 550 had the standard Mercedes Airmatic DC suspension with adaptive damping, the E 63 AMG had the AMG-tuned Airmatic suspension which with the stability control turned off gave it far better driving dynamics than its non-AMG predecessors.


title: Mercedes-Benz E-Class (W211)

text: The AMG Performance package P030 added electronic speed limiter deletion, limited-slip rear differential, Alcantara sports steering wheel, stiffer valving Airmatic suspension over the standard AMG tuned Airmatic, AMG 5-spoke multi-piece wheels, and optional AMG carbon fibre trim.


title: Mercedes-Benz E-Class (W211)

text: The E-Guard was an armoured version with category B4 protection level. Engine choices included E 320 CDI, E 350, and E 500. The vehicles were reinforced with steel and aramid. Other safety equipment included Michelin MOExtended run-flat tyres with pressure loss warning system. All models had a top speed of .


title: Mercedes-Benz E-Class (W211)

text: Common rail Direct Injection with a 7G-Tronic automatic transmission, launched in the US as the E 320 BlueTEC in 2007 and in Europe as the E 300 BlueTEC in 2008. The W211 never had a urea injection system throughout its production. The Bluetec name was only adopted to have consistency between the petrol and diesel nomenclature.


title: Mercedes-Benz E-Class (W211)

text: On 19 December 2008, Mercedes-Benz announced it had delivered 1.5 million units of W211 E-Class vehicles, with 1,270,000 sedans and 230,000 wagons.


title: Seattle–Tacoma International Airport

text: Seattle–Tacoma International Airport , branded as SEA Airport and also referred to as Sea–Tac (), is the primary commercial airport serving the Seattle metropolitan area in the U.S. state of Washington. It is in the city of SeaTac, which was named after the airport’s nickname “Sea-Tac”, approximately south of Downtown Seattle and north-northeast of Downtown Tacoma. The airport, which is the busiest in the Pacific Northwest region of North America, is situated between Portland, Oregon and Vancouver, British Columbia, and is owned by Port of Seattle.


title: Seattle–Tacoma International Airport

text: The entire airport covers an area of . The airport has flights to cities throughout North America, Oceania, Europe, the Middle East, and Asia. It is the primary hub for Alaska Airlines, whose headquarters are near the airport. It is also a hub and international gateway for Delta Air Lines, which has expanded at the airport since 2011. , 31 airlines operate at SEA, serving 91 domestic and 28 international destinations.


title: Seattle–Tacoma International Airport

text: The airport was built by the Port of Seattle in 1944 after the U.S. military took control of Boeing Field in World War II. The Port received $1 million from the Civil Aeronautics Administration to build the airport and $100,000 from the City of Tacoma. The first scheduled airline flights were Northwest and Trans-Canada in 1947; Western and United moved from Boeing Field in the next couple of years, and Pan Am moved in 1952–53, but West Coast and successors Air West and Hughes Airwest stayed at Boeing Field until 1971. The original terminal was designed by architect Herman A. Moldenhour. The official opening ceremony took place on July 9, 1947, in front of a crowd of 30,000.


title: Seattle–Tacoma International Airport

text: In June 1951 four runways were at 45-degree angles, between long; the northeast–southwest and northwest–southeast runways intersected just west of the north–south runway that eventually became today's runway 34R. Runway 34 was lengthened to 7500 ft in 1951, to 8500 ft by 1958, and to 11900 ft by 1962. The extension required the construction of an automobile tunnel for South 188th Street, which opened in July 1961. Runway 34L replaced runway 2 around 1970.


title: Seattle–Tacoma International Airport

text: The April 1957 OAG shows 216 departures a week on United, 80 Northwest, 35 Western, 21 Trans-Canada, 20 Pan Am, 20 Pacific Northern and 10 Alaska. The first jet flights were Pan Am Boeing 707s to Honolulu via Portland (OR) in late 1959 (Pan Am's timetable for September 27 shows a weekly jet). In 1966 Scandinavian Airlines began the airport's first non-stop flight to mainland Europe (Pan Am nonstops to London began around 1961). The first concourse opened in July 1959.


title: Seattle–Tacoma International Airport

text: The two-story North Concourse (later dubbed Concourse D) added four gate positions and a new wing long and wide. The one-story South Concourse (now Concourse A) opened in 1961, adding another to the length of the airport. The long Concourse B opened in December 1964. It added eight gate positions, bringing the total to 19, a area housing international arrivals and the offices of U.S. Customs, Immigration, Public Health and the Department of Agriculture. Concourse C opened in July 1966. Just four years later, it was extended to include another 10 gates, bringing the total to 35. The Port embarked on a major expansion plan, designed by The Richardson Associates and lasting from 1967 to 1973, adding a second runway, a parking garage, two satellite terminals and other improvements. In 1973, $28-million new terminal was built over and around the 1949 structure; the new terminal quadrupled the area for public use. On July 1, 1973, the Airport opened two new satellite terminals, along with an underground train system to connect them to the Main Terminal. In the mid-1980s, the Main Terminal was renovated and another was added to the north end. Concourse D was expanded in 1987 with a rotunda that added four new gates. In 1993, Concourses B, C, and D were renovated. The project, designed by NBBJ, included the addition of and the renovation of of space in Concourses B, C, and D. On June 15, 2004, the new Concourse A was unveiled with 14 new gates, a dozen new restaurants, new artwork and the airport's first moving sidewalks.


title: Seattle–Tacoma International Airport

text: Residents of the surrounding area filed lawsuits against the Port in the early 1970s, complaining of noise, vibration, smoke, and other problems. The Port and the government of King County adopted the Sea–Tac Communities Plan in 1976 to address problems and guide future development. The Port spent more than $100 million over the next decade to buy homes and school buildings in the vicinity, and soundproof others nearby. In the mid-1980s, the airport participated in the airport noise-compatibility program initiated by Congress in 1979. Airport-noise contours were developed, real estate was purchased and some homes were retrofitted to achieve noise mitigation.


title: Seattle–Tacoma International Airport

text: In 1978 the U.S. ended airline regulation, and the U.S. airlines were allowed to determine routes and fares without government approval. Deregulation resulted in some new service to Seattle, including from TWA, then the fourth-largest U.S. airline, as well as Delta, National, and American.


title: Seattle–Tacoma International Airport

text: After the death of U.S. Senator Henry Martin "Scoop" Jackson in 1983, the Seattle Port Commission voted to change the airport's name to the Henry M. Jackson International Airport. Citizens of Tacoma interpreted the change as an insult to their community—the second time in the airport's history that the port authorities had attempted to remove "Tacoma" from the name. The $100,000 Tacoma had provided for the airport's construction during World War II had come with an explicit promise that the city would be included in the airport's name. An additional complicating factor was the existence of another Jackson International Airport (now Jackson–Medgar Wiley Evers International Airport) in Jackson, Mississippi, whose management threatened legal action to preserve its exclusive use of the name. The controversy was resolved after polls of Seattle and Tacoma area residents showed their preference for the original name by margins as much as 5:1. Helen Jackson, the widow of the late Senator Henry M. Jackson, expressed her desire that their family remain neutral in the debate. With a 3–2 vote of the Port of Seattle Commission, the name reverted to Seattle–Tacoma International Airport in early 1984.


title: Seattle–Tacoma International Airport

text: In the late 1980s the Port of Seattle and a council representing local county governments considered the future of air traffic in the region and predicted that the airport could reach capacity by 2000. In 1992, the planning committee concluded that the best solution was to add a third runway to the airport and construct a supplemental two-runway airport in one of the neighboring counties. Members of the community opposed a third runway, as did the Highline School District and the cities of Des Moines, Burien, Federal Way, Tukwila, and Normandy Park, but a 1994 study concluded there were no feasible sites for an additional airport. The Port of Seattle approved a plan for the new runway in 1996, prompting a lawsuit from opponents. The Port secured the necessary permits by agreeing to noise reduction programs and environmental protections. Runway opponents appealed these permits, but dropped their challenges in 2004.


title: Seattle–Tacoma International Airport

text: The airport's Central Terminal building was renovated and expanded in 2003 in a project designed by Curtis W. Fentress, of Fentress Architects.


title: Seattle–Tacoma International Airport

text: The third runway opened on November 20, 2008, with a construction cost of $1.1 billion. Parallel to the existing two, the new runway is 2500 ft west of runway 34R, allowing landings on both in times of low visibility. The older runways are 800 ft apart, too close to allow use of both in low visibility.


title: Seattle–Tacoma International Airport

text: In 2014, Delta Air Lines announced plans to expand Seattle into a transpacific hub. Since then, Delta has added numerous international flights and dozens of domestic flights to feed those services. Delta's increased presence in Seattle has been seen by some industry analysts as a response to United Airlines' transpacific hub at San Francisco, as well as Delta's disenchantment with its former Tokyo–Narita hub.


title: Seattle–Tacoma International Airport

text: In late 2021, shortly after Alaska Airlines joined American Airlines in the Oneworld alliance, American began establishing a hub at the airport to serve destinations in the Asia Pacific region.


title: Seattle–Tacoma International Airport

text: The North Satellite Terminal only received limited upgrades since it opened in 1973, and needed modernization. The Port of Seattle initially looked at simply updating the terminal in a project it called the North Satellite Renovation Plan (NorthSTAR). In 2016, the Port announced it would also significantly expand the terminal. The $550 million project called the North Satellite Modernization increased the size of the North Satellite by 201,000 square feet and another eight gates, bringing the total to 20. The project's first phase, dedicated on July 11, 2019, expanded the terminal to the west by and added eight gates, a mezzanine level with eateries, and a rooftop lounge for Alaska Airlines. The second phase modernized the remaining areas of the old terminal and expands dining and retail space around the twenty existing gates. The new terminal opened on June 29, 2021.


title: Seattle–Tacoma International Airport

text: SEA Airport has seen record growth in passenger traffic over the last few years. That growth has been partly fueled by the nationwide expansion of Seattle-based Alaska Airlines and by Delta Air Lines setting up a major international hub at SEA Airport. That growth has strained the airport's facilities and led the port to invest more than $2 billion into several expansion and renovation projects.


title: Seattle–Tacoma International Airport

text: SEA Airport has six outbound baggage handling systems with limited to no cross-connectivity. The system now in place is aging and reaching its maximum capacity. This $320.4 million project will create one unified, high-speed baggage system under the airport. That will allow bags to be checked from any ticketing counter, to receive security screening faster, and to be routed to any gate in the airport. The extra efficiency and speed will allow the airport to handle more baggage in the future without expanding the footprint of the baggage handling systems. The initial phase of the project was finished in 2018 and the entire system will be in place by 2023.


title: Seattle–Tacoma International Airport

text: The existing customs and immigration facility is located in the basement of the South Satellite, and operates well over its design capacity. Additionally, the process for passengers is complicated by the terminal's isolated location. To address the situation, the Port of Seattle is building a new 450,000-square-foot International Arrivals Facility (IAF) east of Concourse A. The new IAF will be connected to the south satellite by a 900-foot-long bridge (aerial walkway) that will take passengers 85 feet above the existing airplane taxiway and over the top of Concourse A. The project was initially expected to be completed by 2021 at a cost of $766 million. In late 2018, the cost was re-calculated to $968 million.


title: Seattle–Tacoma International Airport

text: After the new IAF opens, the South Satellite will continue to be used for arriving international flights; additional international gates will be added in Concourse A, nearly doubling the number of gates capable of serving arriving international passengers. Once the new International Arrivals Facility is complete, the Port of Seattle will renovate the South Satellite Terminal.


title: Seattle–Tacoma International Airport

text: With estimates that the Puget Sound region will grow by another one million people by 2035, the Port of Seattle began developing the Sustainable Airport Master Plan (SAMP) in 2018 to meet passenger and cargo demands. The SAMP recommends more than 30 projects to improve efficiency and airport access, including a new terminal with 19 gates and an automated people mover through three separate stations. Soon a south satellite renovation will happen too.


title: Seattle–Tacoma International Airport

text: SEA has 103 gates in four concourses and two satellite buildings. The two satellite terminal buildings, named the North and South Satellites, are connected to the four concourses in the main terminal by a three-line automated people mover system called the SEA Underground. The underground transit system moves passengers quickly within the four concourses of the central terminal and out to the two satellite terminals. All non-precleared international arrivals are currently handled at the South Satellite Terminal, regardless of their departure terminal.


title: Seattle–Tacoma International Airport

text: The three parallel runways run nearly north–south, west of the passenger terminal, and are long. In 2018, the airport averaged 1,233 aircraft operations per day, 99% being commercial flights, 1% air taxi operations, and less than 1% transient general aviation and military.


title: Seattle–Tacoma International Airport

text: A new control tower was built beginning in 2001 and opened in November 2004, at the cost of $26 million. The floor of the new tower's control cab is above ground level; the tower's overall height including antennas is . The cab has of space and was designed to support operation by ten controllers, with possible future expansion up to 15. The site and construction method of the tower were designed to maximize the visibility and efficacy of radar systems. The airport's original control tower, built in the 1950s, is now part of the passenger terminal and used as a ramp control tower after being repaired from damage caused by the 2001 Nisqually earthquake.


title: Seattle–Tacoma International Airport

text: A recurring problem at the airport is the misidentification of the westernmost taxiway, Taxiway Tango, as a runway. A large "X" has been placed on the north end of the taxiway, but many aircraft have landed on the taxiway. The FAA issued an alert notice dated from August 27, 2009, to September 24, 2009, urging airplanes about taking precautions such as REILs and other visual cues while landing from the north.


title: Seattle–Tacoma International Airport

text: In 2007, the airport became the first to implement an avian radar system providing 24-hour monitoring of wildlife activity across the airfield. This pilot program, designed and implemented with the assistance of the University of Illinois Center of Excellence for Airport Technology (CEAT), was intended to decrease potentially fatal incidents involving collisions with birds and to provide a test bed for the implementation of the technology in the US, which was expected to begin in 2009. The technology is part of a strategy to reduce the presence of wildlife on the airfield.


title: Seattle–Tacoma International Airport

text: The Seattle office of the National Weather Service operates a weather station at the airport, with a temperature gauge between the center and eastern runways. The airport has served as Seattle's official weather recording location since 1945.


title: Seattle–Tacoma International Airport

text: The site of SEA Airport was chosen partly due to its location along State Route 99, approximately midway between Seattle and Tacoma. Interstate 5 and Interstate 405 also converge near the airport, with an easy connection to the airport via State Route 518 and the Airport Expressway. State Route 509 runs west of the airport, connecting the area to West Seattle. The airport is the largest generator of vehicle trips in the state.


title: Seattle–Tacoma International Airport

text: The Port of Seattle offers paid on-site parking in a 13,000-space garage, notable for being North America's largest parking structure under one roof. Numerous privately owned parking facilities are located off-site near the airport.


title: Seattle–Tacoma International Airport

text: The airport is served by the 1 Line of Sound Transit's Link light rail system at the SeaTac/Airport station with frequent service to downtown Seattle and the University of Washington. The station opened on December 19, 2009, and is connected to the airport terminal via a pedestrian bridge to the airport parking garage. Another pedestrian bridge over International Boulevard is used to access the city of SeaTac, nearby airport hotels, and King County Metro buses including RapidRide A Line. A 1.6-mile extension of the Link line south to Angle Lake Station at South 200th Street opened on September 24, 2016.


title: Seattle–Tacoma International Airport

text: The airport is also served both by the King County Metro bus system and Sound Transit regional express buses. Sound Transit buses offer service to West Seattle, White Center, Burien, Renton, Newcastle and Bellevue through Route 560. In contrast, Route 574 offers service to Lakewood via Des Moines, Federal Way, and Tacoma.


title: Seattle–Tacoma International Airport

text: Tukwila Station, which is approximately 5 miles east of the airport, is served by Sounder commuter rail and Amtrak Cascades regional inter-city rail with service north to Vancouver, Canada, and service south to Portland and Eugene in Oregon. This station can be reached in about 30 minutes via the Central Link light rail or the RapidRide A Line bus service and transferring at Tukwila International Boulevard station to the RapidRide F Line bus service.


title: Seattle–Tacoma International Airport

text: The airport serves door-to-door shuttle services (Shuttle Express and Speedi Shuttle) and several scheduled airporter bus services. Airporters include Bellair Charters to Yakima and Bellingham, and the Quick Shuttle to downtown Vancouver, Canada, through Quick Shuttle, with other pick-up stops at downtown Seattle, Bellingham International Airport, and drop-off stops just inside the Canadian–U.S. boundary and at the Vancouver International Airport.


title: Seattle–Tacoma International Airport

text: A consolidated rental car facility opened on May 17, 2012. The facility is at the northeastern portion of the airport at the intersection of South 160th Street and International Boulevard South. The facility has 5,400 parking spaces and can handle up to 14,000 transactions per day. After the opening of the facility, 3,200 parking spaces in the central parking structure opened for general use. Passengers reach the facility on a five-minute trip aboard one of 29 low-floor Gillig CNG buses. Previously, only Alamo, Avis, Sixt, Budget, Hertz and National had cars on site; Advantage, Dollar, Enterprise, Thrifty, EZ Rent-A-Car and Fox Rent A Car ran shuttles to off-site locations. Payless Car Rental now has a presence. Customers of Rent-a-Wreck must ride the shuttle to the facility and board one of the company's shuttles to Rent-a-Wreck's office.


title: Wildebeest

text: Wildebeest ( , , ), also called gnu ( or ), are antelopes of the genus Connochaetes and native to Eastern and Southern Africa. They belong to the family Bovidae, which includes true antelopes, cattle, goats, sheep, and other even-toed horned ungulates. There are two species of wildebeest: the black wildebeest or white-tailed gnu ("C. gnou"), and the blue wildebeest or brindled gnu ("C. taurinus").


title: Wildebeest

text: Fossil records suggest these two species diverged about one million years ago, resulting in a northern and a southern species. The blue wildebeest remained in its original range and changed very little from the ancestral species, while the black wildebeest changed more as adaptation to its open grassland habitat in the south. The most obvious ways of telling the two species apart are the differences in their colouring and in the way their horns are oriented.


title: Wildebeest

text: In East Africa, the blue wildebeest is the most abundant big-game species; some populations perform an annual migration to new grazing grounds, but the black wildebeest is merely nomadic. Breeding in both takes place over a short period of time at the end of the rainy season and the calves are soon active and are able to move with the herd, a fact necessary for their survival. Nevertheless, some fall prey to large carnivores, especially the spotted hyena.


title: Wildebeest

text: Wildebeest often graze in mixed herds with zebra, which gives heightened awareness of potential predators. They are also alert to the warning signals emitted by other animals such as baboons. Wildebeest are a tourist attraction but compete with domesticated livestock for pasture and are sometimes blamed by farmers for transferring diseases and parasites to their cattle. Illegal hunting does take place but the population trend is fairly stable. Wildebeest can also be found in national parks or on private land. The International Union for Conservation of Nature lists both kinds of wildebeest as least-concern species.


title: Wildebeest

text: is Dutch for "wild beast" or "wild cattle" in Afrikaans ("bees" "cattle"), while "Connochaetes" derives from the Ancient Greek words , , "beard", and χαίτη, , "flowing hair", "mane". Some sources claim the name "gnu" originates from the Khoekhoe name for these animals, "t'gnu". Others contend the name and its pronunciation in English go back to the word "!nu:"used for the black wildebeest by the San people.


title: Wildebeest

text: The wildebeest, genus "Connochaetes", is placed under the family Bovidae and subfamily Alcelaphinae, where its closest relatives are the hartebeest ("Alcelaphus" spp.), the hirola ("Beatragus hunteri"), and species in the genus "Damaliscus", such as the topi, the tsessebe, the blesbok and the bontebok. The name "Connochaetes" was given by German zoologist Hinrich Lichtenstein in 1812.


title: Wildebeest

text: Dutch settlers first discovered wildebeest in about 1700, on their way to the interior of South Africa. Due to their resemblance to wild cattle, these people called them "wild ox" or "wildebeest". The blue wildebeest was first known to westerners in the northern part of South Africa a century later, in the 1800s.


title: Wildebeest

text: In the early 20th century, one species of the wildebeest, "C. albojubatus", was identified in eastern Africa. In 1914, two separate races of the wildebeest were introduced, namely "Gorgon a. albojubatus" ("Athi white-bearded wildebeest") and "G. a. mearnsi" ("Loita white-bearded wildebeest"). However, in 1939, the two were once again merged into a single race, "Connochaetes taurinus albojubatus". In the mid-20th century, two separate forms were recognised, "Gorgon taurinus hecki" and "G. t. albojubatus". Finally, two distinct types of wildebeest – the blue and black wildebeest – were identified. The blue wildebeest was at first placed under a separate genus, "Gorgon", while the black wildebeest belonged to the genus "Connochaetes". Today, they are united in the single genus "Connochaetes", with the black wildebeest being named ("C. gnou") and the blue wildebeest ("C. taurinus").


title: Wildebeest

text: According to a mitochondrial DNA analysis, the black wildebeest are estimated to have diverged from the main lineage during the Middle Pleistocene and became a distinct species around a million years ago. A divergence rate around 2% has been calculated. The split does not seem to have been driven by competition for resources, but instead because each species adopted a different ecological niche and occupied a different trophic level.


title: Wildebeest

text: Blue wildebeest fossils dating back some 2.5 million years ago are common and widespread. They have been found in the fossil-bearing caves at the Cradle of Humankind north of Johannesburg. Elsewhere in South Africa, they are plentiful at such sites as Elandsfontein, Cornelia, and Florisbad. The earliest fossils of the black wildebeest were found in sedimentary rock in Cornelia in the Free State and dated back about 800,000 years. Today, five subspecies of the blue wildebeest are recognised, while the black wildebeest has no named subspecies.


title: Wildebeest

text: The diploid number of chromosomes in the wildebeest is 58. Chromosomes were studied in a male and a female wildebeest. In the female, all except a pair of very large submetacentric chromosomes were found to be acrocentric. Metaphases were studied in the male's chromosomes, and very large submetacentric chromosomes were found there, as well, similar to those in the female both in size and morphology. Other chromosomes were acrocentric. The X chromosome is a large acrocentric and the Y chromosome a minute one.


title: Wildebeest

text: The two species of the wildebeest are known to hybridise. Male black wildebeest have been reported to mate with female blue wildebeest and vice versa. The differences in social behaviour and habitats have historically prevented interspecific hybridisation between the species, but hybridisation may occur when they are both confined within the same area. The resulting offspring are usually fertile. A study of these hybrid animals at Spioenkop Dam Nature Reserve in South Africa revealed that many had disadvantageous abnormalities relating to their teeth, horns, and the wormian bones in the skull. Another study reported an increase in the size of the hybrid as compared to either of its parents. In some animals, the tympanic part of the temporal bone is highly deformed, and in others, the radius and ulna are fused.