Roman emperor

The Roman Emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of different titles throughout history. Often when a given Roman is described as becoming "emperor" in English, it reflects his taking of the title "Augustus" or "Caesar". Another title often used was "imperator", originally a military honorific. Early emperors also used the title "Princeps Civitatis" ('first citizen'). Emperors frequently amassed republican titles, notably "princeps senatus", "consul," and "pontifex maximus".
The legitimacy of an emperor's rule depended on his control of the army and recognition by the Senate; an emperor would normally be proclaimed by his troops, or invested with imperial titles by the Senate, or both. The first emperors reigned alone; later emperors would sometimes rule with co-emperors and divide administration of the empire between them.
The Romans considered the office of emperor to be distinct from that of a king. The first emperor, Augustus, resolutely refused recognition as a monarch. For the first three hundred years of Roman emperors, from Augustus until Diocletian, efforts were made to portray the emperors as leaders of the republic, fearing any association with the kings of Rome prior to the Republic.
From Diocletian, whose tetrarchic reforms also divided the position into one emperor in the West and one in the East, until the end of the Empire, emperors ruled in an openly monarchic style and did not preserve the nominal principle of a republic, but the contrast with "kings" was maintained: although the imperial succession was generally hereditary, it was only hereditary if there was a suitable candidate acceptable to the army and the bureaucracy, so the principle of automatic inheritance was not adopted. Elements of the republican institutional framework (senate, consuls, and magistrates) were preserved even after the end of the Western Empire.
The reign of Constantine the Great witnessed the removal of the Caput Mundi from Rome to Constantinople, formerly known as Byzantium, in 330 AD. The Western Roman Empire collapsed in the late 5th century after multiple invasions of imperial territory by Germanic barbarian tribes. Romulus Augustulus is often considered to have been the last emperor of the West, until his forced abdication in 476, although Julius Nepos maintained a claim recognized by the Eastern Empire to the title until his death in 480. Following Nepos' death, the Eastern emperor Zeno abolished the division of the position and proclaimed himself as the sole emperor of a reunited Roman Empire. Emperor Heraclius made diplomatic relations with the Companions of the Prophet Muhammad, but lost many territories after successful Islamic conquests. The Eastern imperial lineage continued to rule from Constantinople ("New Rome"); they continued to style themselves "emperor of the Romans" (later βασιλεύς Ῥωμαίων in Greek), but are often referred to in modern scholarship as Byzantine emperors. Constantine XI Palaiologos was the last Roman emperor in Constantinople, dying in the Fall of Constantinople to the Ottoman Empire's Mehmed II in 1453. The Muslim rulers then claimed the title of Caesar of Rome.
The "Byzantine" emperors from Heraclius in 629 and onwards adopted the title of "basileus" (), which had originally meant "king" in Greek but became a title reserved solely for the Roman emperor and the ruler of the Sasanian Empire. Other kings were then referred to as "rēgas".
In addition to their pontifical office, some emperors were given divine status after death. With the eventual hegemony of Christianity, the emperor came to be seen as God's chosen ruler, as well as a special protector and leader of the Christian Church on Earth, although in practice an emperor's authority on Church matters was subject to challenge.
Due to the cultural rupture of the Turkish conquest, most western historians treat Constantine XI as the last meaningful claimant to the title Roman emperor. From 1453, one of the titles used by the Ottoman Sultans was "Caesar of Rome" (Turkish: "Kayser-i Rum"), part of their titles until the Ottoman Empire ended in 1922. A Byzantine group of claimant Roman emperors existed in the Empire of Trebizond until its conquest by the Ottomans in 1461, though they had used a modified title since 1282.
Eastern emperors in Constantinople had been recognized and accepted as Roman emperors both in the East, which they ruled, and by the papacy and Germanic kingdoms of the West until the deposition of Constantine VI and accession of Irene of Athens as Empress regnant in 797. Objecting to a woman ruling the Roman Empire in her own right and issues with the eastern clergy, the Papacy would then create a rival lineage of Roman emperors in western Europe, the Holy Roman Emperors, which ruled the Holy Roman Empire for most of the period between 800 and 1806. These emperors were never recognized as Roman emperors by the court in Constantinople and their coronations resulted in the medieval problem of two emperors.
Background and beginning.
Modern historians conventionally regard Augustus as the first Emperor whereas Julius Caesar is considered the last dictator of the Roman Republic, a view having its origins in the Roman writers Plutarch, Tacitus and Cassius Dio. However, the majority of Roman writers, including Josephus, Pliny the Younger, Suetonius and Appian, as well as most of the ordinary people of the Empire, thought of Julius Caesar as the first Emperor.
At the end of the Roman Republic no new, and certainly no single, title indicated the individual who held supreme power. Insofar as "emperor" could be seen as the English translation of imperator, then Julius Caesar had been an emperor, like several Roman generals before him. Instead, by the end of the civil wars in which Julius Caesar had led his armies, it became clear that there was certainly no consensus to return to the old-style monarchy, but that the period when several officials, bestowed with equal power by the senate, would fight one another had come to an end.
Julius Caesar, and then Augustus after him, accumulated offices and titles of the highest importance in the Republic, making the power attached to those offices permanent, and preventing anyone with similar aspirations from accumulating or maintaining power for themselves. However, Julius Caesar, unlike those after him, did so without the Senate's vote and approval.
Julius Caesar held the Republican offices of consul four times and dictator five times, was appointed dictator in perpetuity ("dictator perpetuo") in 45 BC and had been "pontifex maximus" for a long period. He gained these positions by senatorial consent and just prior to his assassination, 
was the most powerful man in the Roman world.
In his will, Caesar appointed his adopted son Octavian as his heir. On Caesar's death, Octavian inherited his adoptive father's property and lineage, the loyalty of most of his allies and – again through a formal process of senatorial consent – an increasing number of the titles and offices that had accrued to Caesar. A decade after Caesar's death, Octavian's victory over his erstwhile ally Mark Antony at Actium put an end to any effective opposition and confirmed Octavian's supremacy.
In 27 BC, Octavian appeared before the Senate and offered to retire from active politics and government; the Senate not only requested he remain, but increased his powers and made them lifelong, awarding him the title of "Augustus" (the elevated or divine one, somewhat less than a god but approaching divinity). Augustus stayed in office until his death; the sheer breadth of his superior powers as "princeps" and permanent "imperator" of Rome's armies guaranteed the peaceful continuation of what nominally remained a republic. His "restoration" of powers to the Senate and the people of Rome was a demonstration of his "auctoritas" and pious respect for tradition.
Some later historians such as Tacitus would say that even at Augustus' death, the true restoration of the Republic might have been possible. Instead, Augustus actively prepared his adopted son Tiberius to be his successor and pleaded his case to the Senate for inheritance on merit. The Senate disputed the issue but eventually confirmed Tiberius as "princeps". Once in power, Tiberius took considerable pains to observe the forms and day-to-day substance of republican government.
Classical period.
Rome had no single constitutional office, title or rank exactly equivalent to the English title "Roman emperor". Romans of the Imperial era used several titles to denote their emperors, and all were associated with the pre-Imperial, Republican era.
The legal authority of the emperor derived from an extraordinary concentration of individual powers and offices that were extant in the Republic rather than from a new political office; emperors were regularly elected to the offices of consul and censor. Among their permanent privileges were the traditional Republican title of "princeps senatus" (leader of the Senate) and the religious office of "pontifex maximus" (chief priest of the College of Pontiffs). Every emperor held the latter office and title until Gratian surrendered it in AD 382 to Pope Siricius; it eventually became an auxiliary honor of the Bishop of Rome.
These titles and offices conferred great personal prestige ("dignitas") but the basis of an emperor's powers derived from his "auctoritas": this assumed his greater powers of command ("imperium maius") and tribunician power ("tribunicia potestas") as personal qualities, separate from his public office. As a result, he formally outranked provincial governors and ordinary magistrates. He had the right to enact or revoke sentences of capital punishment, was owed the obedience of private citizens ("privati") and by the terms of the "ius auxiliandi" could save any plebeian from any patrician magistrate's decision. He could veto any act or proposal of any magistrate, including the tribunes of the people ("ius intercedendi" or "ius intercessionis"). His person was held to be sacred.
Roman magistrates on official business were expected to wear the form of toga associated with their office; different togas were worn by different ranks; senior magistrates had the right to togas bordered with purple. A triumphal "imperator" of the Republic had the right to wear the "toga picta" (of solid purple, richly embroidered) for the duration of the triumphal rite. During the Late Republic, the most powerful had this right extended. Pompey and Caesar are both thought to have worn the triumphal toga and other triumphal dress at public functions. Later emperors were distinguished by wearing "togae purpurae", purple togas; hence the phrase "to don the purple" for the assumption of imperial dignity.
The titles customarily associated with the imperial dignity are "imperator" ("commander"), which emphasizes the emperor's military supremacy and is the source of the English word "emperor"; "Caesar", which was originally a name but came to be used for the designated heir (as "Nobilissimus Caesar", "Most Noble Caesar") and was retained upon accession. The ruling emperor's title was the descriptive "Augustus" ("majestic" or "venerable", which had tinges of the divine), which was adopted upon accession. In Greek, these three titles were rendered as "autokratōr" (""), "kaisar" (""), and "augoustos" ("") or "sebastos" ("") respectively. In Diocletian's Tetrarchy, the traditional seniorities were maintained: "Augustus" was reserved for the two senior emperors and "Caesar" for the two junior emperors – each delegated a share of power and responsibility but each an emperor-in-waiting, should anything befall his senior.
As "princeps senatus" (lit., "first man of the senate"), the emperor could receive foreign embassies to Rome; some emperors (such as Tiberius) are known to have delegated this task to the Senate. In modern terms, these early emperors would tend to be identified as chiefs of state. The office of "princeps senatus", however, was not a magistracy and did not entail "imperium". At some points in the Empire's history, the emperor's power was nominal; powerful praetorian prefects, masters of the soldiers and on a few occasions, other members of the Imperial household including Imperial mothers and grandmothers were the true source of power.
"Imperator".
The title "imperator" dates back to the Roman Republic, when a victorious commander could be hailed as "imperator" in the field by his troops. The Senate could then award or withhold the extraordinary honour of a triumph; the triumphal commander retained the title until the end of his magistracy. In Roman tradition, the first triumph was that of Romulus, but the first attested recipient of the title "imperator" in a triumphal context is Aemilius Paulus in 189 BC. It was a title held with great pride: Pompey was hailed "imperator" more than once, as was Sulla, but it was Julius Caesar who first used it permanently – according to Dio, this was a singular and excessive form of flattery granted by the Senate, passed to Caesar's adopted heir along with his name and virtually synonymous with it.
In 38 BC, Agrippa refused a triumph for his victories under Octavian's command, and this precedent established the rule that the "princeps" should assume both the salutation and title of "imperator". It seems that from then on Octavian (later the first emperor Augustus) used "imperator" as a first name ("praenomen"): "Imperator Caesar" not "Caesar imperator". From this the title came to denote the supreme power and was commonly used in that sense. Otho was the first to imitate Augustus, but only with Vespasian did "imperator" (emperor) become the official title by which the ruler of the Roman Empire was known.
"Princeps".
The word "princeps" (plural "principes"), meaning "first", was a republican term used to denote the leading citizen(s) of the state. It was a purely honorific title with no attached duties or powers. It was the title most preferred by Augustus as its use implies only primacy, as opposed to another of his titles, "imperator", which implies dominance. "Princeps", because of its republican connotation, was most commonly used to refer to the emperor in Latin (although the emperor's actual constitutional position was essentially "pontifex maximus with tribunician power and "imperium" superseding all others") as it was in keeping with the façade of the restored Republic; the Greek word "basileus" ("king") was modified to be synonymous with emperor (and primarily came into favour after the reign of Heraclius) as the Greeks had no republican sensibility and openly viewed the emperor as a monarch.
In the era of Diocletian and beyond, "princeps" fell into disuse and was replaced with "dominus" ("lord"); later emperors used the formula "Imperator Caesar NN. Pius Felix (Invictus) Augustus": NN representing the individual's personal name; Pius Felix meaning "Pious and Blest"; and Invictus meaning "undefeated". The use of "princeps" and "dominus" broadly symbolise the differences in the empire's government, giving rise to the era designations "Principate" and "Dominate".
Evolution in Late Antiquity.
In 293, following the Crisis of the Third Century which had severely damaged Imperial administration, Emperor Diocletian enacted sweeping reforms that washed away many of the vestiges and façades of republicanism which had characterized the Augustan order in favor of a more frank autocracy. As a result, historians distinguish the Augustan period as the principate and the period from Diocletian to the 7th-century reforms of Emperor Heraclius as the dominate (from the Latin for "lord".)
Reaching back to the oldest traditions of job-sharing in the republic, however, Diocletian established at the top of this new structure the Tetrarchy ("rule of four") in an attempt to provide for smoother succession and greater continuity of government. Under the Tetrarchy, Diocletian set in place a system of co-emperors, styled "Augustus", and junior emperors, styled "Caesar". When a co-emperor retired (as Diocletian and his co-emperor Maximian did in 305) or died, a junior "Caesar" would succeed him and the co-emperors would appoint new Caesars as needed.
The four members of the Imperial college (as historians call the arrangement) shared military and administrative challenges by each being assigned specific geographic areas of the empire. From this innovation, often but not consistently repeated over the next 187 years, comes the notion of an east–west partition of the empire that became popular with historians long after the practice had stopped. The two halves of empire, while often run as "de facto" separate entities day-to-day, were always considered and seen, legally and politically, as separate administrative divisions of a single, insoluble "imperium" by the Romans of the time.
When emperor Theodosius I died, his sons Arcadius and Honorius, already proclaimed "augusti", succeeded him. Eighty-five years later, following Germanic migrations which had reduced the empire's effective control across Brittania, Gaul and Hispania and a series of military coup d'état which drove Emperor Nepos out of Italy, the idea of dividing the position of emperor was formally abolished by Emperor Zeno (480).
The Roman Empire survived in the east until 1453, but the marginalization of the former heartland of Italy to the empire had a profound cultural impact on the empire and the position of emperor. The Greek-speaking inhabitants were "Romaioi" (Ῥωμαῖοι), and were still considered Romans by themselves and the populations of Eastern Europe, the Near East, India, and China. But many in Western Europe began to refer to the political entity as the "Greek Empire". The evolution of the church in the no-longer imperial city of Rome and the church in the now supreme Constantinople began to follow divergent paths, culminating in the schism between the Roman Catholic and Eastern Orthodox faiths. The position of emperor was increasingly influenced by Near Eastern concepts of kingship. Starting with Emperor Heraclius, Roman emperors styled themselves "King of Kings" (from the imperial Persian "Shahanshah") from 627 and "Basileus" (from the title used by Alexander the Great) from 629. The later period of the empire is today called the Byzantine Empire as a matter of scholarly convention.
Titles and positions.
Although these are the most common offices, titles, and positions, not all Roman emperors used them, nor were all of them used at the same time in history. The consular and censorial offices especially were not an integral part of the Imperial dignity, and were usually held by persons other than the reigning emperor.
Powers.
When Augustus established the "Princeps", he turned down supreme authority in exchange for a collection of various powers and offices, which in itself was a demonstration of his "auctoritas" ("authority"). As holding "princeps senatus", the emperor declared the opening and closure of each Senate session, declared the Senate's agenda, imposed rules and regulation for the Senate to follow, and met with foreign ambassadors in the name of the Senate. Being "pontifex maximus" made the emperor the chief administrator of religious affairs, granting him the power to conduct all religious ceremonies, consecrate temples, control the Roman calendar (adding or removing days as needed), appoint the vestal virgins and some flamens, lead the Collegium Pontificum, and summarize the dogma of the Roman religion.
While these powers granted the emperor a great deal of personal pride and influence, they did not include legal authority. In 23 BC, Augustus gave the emperorship its legal power. The first was "Tribunicia Potestas", or the powers of the tribune of the plebs without actually holding the office (which would have been impossible, since a tribune was by definition a plebeian, whereas Augustus, although born into a plebeian family, had become a patrician when he was adopted into the "gens Julia"). This endowed the emperor with inviolability (sacrosanctity) of his person, and the ability to pardon any civilian for any act, criminal or otherwise. By holding the powers of the tribune, the emperor could prosecute anyone who interfered with the performance of his duties. The emperor's tribuneship granted him the right to convene the Senate at his will and lay proposals before it, as well as the ability to veto any act or proposal by any magistrate, including the actual tribune of the plebeians. Also, as holder of the tribune's power, the emperor would convoke the Council of the People, lay legislation before it, and served as the council's president. But his tribuneship only granted him power within Rome itself. He would need another power to veto the act of governors and that of the consuls while in the provinces.
To solve this problem, Augustus managed to have the emperor be given the right to hold two types of imperium. The first being "consular imperium" while he was in Rome, and "imperium maius" outside of Rome. While inside the walls of Rome, the reigning consuls and the emperor held equal authority, each being able to veto each other's proposals and acts, with the emperor holding all of the consul's powers. But outside of Rome, the emperor outranked the consuls and could veto them without the same effects on himself. Imperium Maius also granted the emperor authority over all the provincial governors, making him the ultimate authority in provincial matters and gave him the supreme command of all of Rome's legions. With Imperium Maius, the emperor was also granted the power to appoint governors of imperial provinces without the interference of the Senate. Also, Imperium Maius granted the emperor the right to veto the governors of the provinces and even the reigning consuls while in the provinces.
Normally, the powers vested in Augustus would have been split between several people, who would each exercise them with the assistance of a colleague and for a specific period of time. Augustus held them all at once by himself, and with no time limits; even those that nominally had time limits were automatically renewed whenever they lapsed.
Lineages and epochs.
Principate.
The nature of the imperial office and the Principate was established under Julius Caesar's heir and posthumously adopted son, Augustus, and his own heirs, the descendants of his wife Livia from her first marriage to a scion of the distinguished Claudian clan. This Julio-Claudian dynasty came to an end when the Emperor Nero – a great-great-grandson of Augustus through his daughter and of Livia through her son – was deposed in 68.
Nero was followed by a succession of usurpers throughout 69, commonly called the "Year of the Four Emperors". The last of these, Vespasian, established his own Flavian dynasty. Nerva, who replaced the last Flavian emperor, Vespasian's son Domitian, in 96, was elderly and childless, and chose therefore to adopt an heir, Trajan, from outside his family. When Trajan acceded to the purple he chose to follow his predecessor's example, adopting Hadrian as his own heir, and the practice then became the customary manner of imperial succession for the next century, producing the "Five Good Emperors" and the Empire's period of greatest stability.
The last of the Good Emperors, Marcus Aurelius, chose his natural son Commodus as his successor rather than adopting an heir. A brief period of instability quickly gave way to Septimius Severus, who established the Severan dynasty which, except for an interruption in 217–218 when Macrinus was emperor, held the purple until 235.
Crisis of the Third Century.
The accession of Maximinus Thrax marks both the close and the opening of an era. It was one of the last attempts by the increasingly impotent Roman Senate to influence the succession. Yet it was the second time that a man had achieved the purple while owing his advancement purely to his military career; both Vespasian and Septimius Severus had come from noble or middle-class families, while Thrax was born a commoner. He never visited the city of Rome during his reign, which marks the beginning of a series of "barracks emperors" who came from the army. Between 235 and 285 over a dozen emperors achieved the purple, but only Valerian and Carus managed to secure their own sons' succession to the throne; both dynasties died out within two generations.
Dominate.
The accession on 20 November 284, of Diocletian, the lower-class, Greek-speaking Dalmatian commander of Carus' and Numerian's household cavalry ("protectores domestici"), marked major innovations in Rome's government and constitutional theory. Diocletian, a traditionalist and religious conservative, attempted to secure efficient, stable government and a peaceful succession with the establishment of the Tetrarchy. The empire was divided into East and West, each ruled by an Augustus assisted by a Caesar as emperor-in-waiting. These divisions were further subdivided into new or reformed provinces, administered by a complex, hierarchic bureaucracy of unprecedented size and scope. Diocletian's own court was based at Nicomedia. His co-Augustus, Maximian, was based at Mediolanum (modern Milan). Their courts were peripatetic, and Imperial progressions through the provinces made much use of the impressive, theatrical adventus, or "Imperial arrival" ceremony, which employed an elaborate choreography of etiquette to emphasise the emperor's elevation above other mortals. Hyperinflation of imperial honours and titles served to distinguish the "Augusti" from their "Caesares", and Diocletian, as senior "Augustus", from his colleague Maximian. The senior "Augustus" in particular was made a separate and unique being, accessible only through those closest to him. The overall unity of the Empire still required the highest investiture of power and status in one man.
The Tetrarchy ultimately degenerated into civil war, but the eventual victor, Constantine the Great, restored Diocletian's division of Empire into East and West. He kept the East for himself and founded his city of Constantinople as its new capital. Constantine's own dynasty was also soon swallowed up in civil war and court intrigue until it was replaced, briefly, by Julian the Apostate's general Jovian and then, more permanently, by Valentinian I and the dynasty he founded in 364. Though a soldier from a low middle-class background, Valentinian was made emperor by a conclave of senior generals and civil officials.
Theodosius I acceded to the purple in the East in 379 and in the West in 394. He outlawed paganism and made Christianity the Empire's official religion. He was the last emperor to rule over a united Roman Empire; the distribution of the East to his son Arcadius and the West to his son Honorius after his death in 395 represented a permanent division.
Decline of the Western Roman Empire.
In the Western Roman Empire, the office of emperor soon degenerated into being little more than a puppet of a succession of Germanic tribal kings, until finally the Heruli Odoacer simply overthrew the child-emperor Romulus Augustulus in 476, shipped the imperial regalia to the Emperor Zeno in Constantinople and became King of Italy.
Though during his own lifetime Odoacer maintained the legal fiction that he was actually ruling Italy as the viceroy of Zeno, historians mark 476 as the traditional date of the fall of the Western Roman Empire. Large parts of Italy (Sicily, the south part of the peninsula, Ravenna, Venice etc.), however, remained under actual imperial rule from Constantinople for centuries, with imperial control slipping or becoming nominal only as late as the 11th century. In the East, the Empire continued until the fall of Constantinople to the Ottoman Turks in 1453. Although known as the Byzantine Empire by contemporary historians, the Empire was simply known as the Roman Empire to its citizens and neighboring countries.
Post-classical assertions to the title.
Survival of the Roman Empire in the East.
The line of Roman emperors in the Eastern Roman Empire continued unbroken at Constantinople until the capture of Constantinople in 1204 by the Fourth Crusade. In the wake of this action, four lines of Emperors emerged, each claiming to be the legal successor: the Empire of Thessalonica, evolving from the Despotate of Epirus, which was reduced to impotence when its founder Theodore Komnenos Doukas was defeated, captured and blinded by the Bulgarian Emperor Ivan Asen III; the Latin Empire, which came to an end when the Empire of Nicaea recovered Constantinople in 1261; the Empire of Trebizond, whose importance declined over the 13th century, and whose claims were simply ignored; and the Empire of Nicaea, whose claims based on kinship with the previous emperors, control of the Patriarch of Constantinople, and possession of Constantinople through military prowess, prevailed. The successors of the emperors of Nicaea continued until the fall of Constantinople in 1453 under Constantine XI Palaiologos.
These emperors eventually normalized the imperial dignity into the modern conception of an emperor, incorporated it into the constitutions of the state, and adopted the aforementioned title "Basileus kai autokratōr Rhomaiōn" ("Emperor and Autocrat of the Romans"). They had also ceased to use Latin as the language of state after Emperor Heraclius (d. 641 AD). Historians have customarily treated the state of these later Eastern emperors under the name "Byzantine Empire". It is important to note, however, that the adjective "Byzantine", although historically used by Eastern Roman authors in a metonymic sense, was never an official term.
Last Roman emperor.
Constantine XI Palaiologos was the last reigning Roman emperor. A member of the Palaiologos dynasty, he ruled the remnant of the Eastern Roman Empire from 1449 until his death in 1453 defending its capital Constantinople.
He was born in Mystra as the eighth of ten children of Manuel II Palaiologos and Helena Dragaš, the daughter of the Serbian prince Constantine Dragaš of Kumanovo. He spent most of his childhood in Constantinople under the supervision of his parents. During the absence of his older brother in Italy, Constantine was regent in Constantinople from 1437 to 1440.
Before the beginning of the siege, Mehmed the Conqueror made an offer to Constantine XI. In exchange for the surrender of Constantinople, the emperor's life would be spared and he would continue to rule in Mystra. Constantine refused this offer. Instead he led the defense of the city and took an active part in the fighting along the land walls. At the same time, he used his diplomatic skills to maintain the necessary unity between the Genovese, Venetian, and Byzantine troops. As the city fell on May 29, 1453, Constantine is said to have remarked: "The city is fallen but I am alive." Realizing that the end had come, he reportedly discarded his purple cloak and led his remaining soldiers into a final charge, in which he was killed. With his death, Roman imperial succession came to an end, almost 1500 years after Augustus.
After the fall of Constantinople, Thomas Palaiologos, brother of Constantine XI, was elected emperor and tried to organize the remaining forces. His rule came to an end after the fall of the last major Byzantine city, Corinth. He then moved in Italy and continued to be recognized as Eastern emperor by the Christian powers.
His son Andreas Palaiologos continued claims on the Byzantine throne until he sold the title to Ferdinand of Aragon and Isabella of Castile, the grandparents of Holy Roman Emperor Charles V.
New Western lineage.
The concept of the Roman Empire was renewed in the West with the coronation of the king of the Franks, Charlemagne (Charles the Great), as Roman emperor by the Pope on Christmas Day, 800. This coronation had its roots in the decline of influence of the Pope in the affairs of the Byzantine Empire at the same time the Byzantine Empire declined in influence over politics in the West. The Pope saw no advantage to be derived from working with the Byzantine Empire, but as George Ostrogorsky points out, "an alliance with the famous conqueror of the Lombards, on the other hand ... promised much".
The immediate response of the Eastern Roman emperor was not welcoming. "At that time it was axiomatic that there could be only one Empire as there could be only one church", writes Ostrogorsky. "The coronation of Charles the Great violated all traditional ideas and struck a hard blow at Byzantine interests, for hitherto Byzantium, the new Rome, had unquestionably been regarded as the sole Empire which had taken over the inheritance of the old Roman "imperium". Conscious of its imperial rights, Byzantium could only consider the elevation of Charles the Great to be an act of usurpation."
Nikephoros I chose to ignore Charlemagne's claim to the imperial title, clearly recognizing the implications of this act. According to Ostrogorsky, "he even went so far as to refuse the Patriarch Nicephorus permission to dispatch the customary "synodica" to the Pope." Meanwhile, Charlemagne's power steadily increased: he subdued Istria and several Dalmatian cities during the reign of Irene, and his son Pepin brought Venice under Western hegemony, despite a successful counter-attack by the Byzantine fleet. Unable to counter this encroachment on Byzantine territory, Nikephoros' successor Michael I Rangabe capitulated; in return for the restoration of the captured territories, Michael sent Byzantine delegates to Aachen in 812 who recognized Charlemagne as "Basileus". Michael did not recognize him as "Basileus" of the Romans, however, which was a title that he reserved for himself.
This line of Roman emperors was actually generally Germanic rather than Roman, but maintained their Roman-ness as a matter of principle. These emperors used a variety of titles (most frequently "Imperator Augustus") before finally settling on "Imperator Romanus Electus" ("Elected Roman Emperor"). Historians customarily assign them the title "Holy Roman Emperor", which has a basis in actual historical usage, and treat their "Holy Roman Empire" as a separate institution. To Latin Catholics of the time, the Pope was the temporal authority as well as spiritual authority, and as Bishop of Rome he was recognized as having the power to anoint or crown a new Roman emperor. The last man to be crowned by the pope (although in Bologna, not Rome) was Charles V. All his successors bore only a title of "Elected Roman Emperor".
This line of Emperors lasted until 1806 when Francis II dissolved the Empire during the Napoleonic Wars. Despite the existence of later potentates styling themselves "emperor", such as the Napoleons, the Habsburg Emperors of Austria, and the Hohenzollern heads of the German Reich, this marked the end of the Western Empire. Although there is a living heir, Karl von Habsburg, to the Habsburg dynasty, as well as a Pope and pretenders to the positions of the electors, and although all the medieval coronation regalia are still preserved in Austria, the legal abolition of all aristocratic prerogatives of the former electors and the imposition of republican constitutions in Germany and Austria render quite remote any potential for a revival of the Holy Roman Empire.