Battle of Brenta

The Battle of Brenta was fought between the cavalry of the Kingdom of Italy under king Berengar I and the Hungarians, hired by the East Francian king Arnulf of Carinthia, against him, at an unidentified location in northern Italian Peninsula along the river Brenta on 24 September 899. It was one of the earliest battles of the Hungarian invasions of Europe. The result was a crushing defeat for Berengar I, opening the following raids for the Hungarians against Italy. The Hungarian invasion resulted in the burning of many cities, like Feltre, Vercelli, Modena and monasteries like the monastery in Nonantola, and attacking even Venice, however without success.
In the meantime Berengar's arch enemy, Arnulf of Carinthia died in December 899, as a result the Hungarians, whom he hired against the Italian king, left the kingdom in the next year with all their plunder, not before concluding peace with Berengar, who gave them many hostages and "gifts". On their way home the Hungarians made an "amphibious assault", a unique achievement from an exclusively land army in the pre-modern times, crossing the Adriatic Sea in order to attack Venice.
In some historians' opinion the returning army had a role also in the conquering of Pannonia, as part of the Hungarian conquest of the Carpathian Basin, from the Bavarians by the Hungarians in late 900.
Sources.
Many contemporary sources mention this battle, like the "Chronicon" of Regino of Prüm, the "Annales Fuldenses", the "Chronicon Sagornini" of John the Deacon, "Catalogus abbatum nonantulorum", etc. The most important source is "Antapodosis, seu rerum per Europam gestarum", written by Liutprand of Cremona, which gives the most detailed description of the events which led to the battle and battle itself.
Background.
At the end of the IX. century the Carolingian Empire of Charlemagne was long gone, in its place remained three kingdoms (West Francia, East Francia, Kingdom of Italy (Holy Roman Empire)), led by kings of Carolingian bloodline, which disputed the supremacy among them. Arnulf of Carinthia, the son of the East Francian king Carloman, who became German king in 887, wanted to recreate the Carolingian Empire, thus in 894, as result of his Italian campaign, became King of Italy, and in 896 he was even crowned as Holy Roman Emperor at Rome by the pope. To his goals in Italy he was helped by Berengar of Friuli, the great-grandson of Charlemagne, who after 898 started to see himself more worthy for the title of emperor, because he considered himself as a truer Carolingian than Arnulf, considering the latter to be an illegitimate son of Carloman. 
Berengar was king of Italy from 888 but lost his lands to Guy III of Spoleto who proclaimed himself king of Italy and emperor. Berengar was saved by the intervention of Arnulf of Carinthia in 894, defeating Guy of Spoleto, who died shortly after. Arnulf in 896, crowned himself as King of Italy (and emperor), but named his illegitimate son Ratold as sub-king of Italy. Ratold and Berengar agreed to divide Italy between themselves, but shortly after they started to fight for supremacy. Ratold died unexpectedly, so Berengar remained as single ruler, and started to aspire for the title of emperor. Aware of this, Arnulf, very ill, could not go personally in campaign in Italy, but concluded an alliance with the leaders of the Hungarians, who in 895-896 occupied the Eastern parts of the Carpathian Basin, convincing them to send an army to attack Berengar. Arnulf was accused by enemies that he concluded the alliance with the Hungarians by cutting a dog and a wolf in two. This was the way of making alliances by the nomadic people, the parties swearing that they will keep the alliance, and cursed themselves to die like the animals they cut in half if they broke their oath. So, probably beside the Christian way, about which the chronicles do not write anything, Arnulf had to conclude this alliance also in the Hungarians "pagan" way. This shows that Arnulf was aware of the Hungarian danger for the Eastern provinces of his realm: mainly the March of Pannonia. So with this alliance had two purposes: to punish Berengar and to divert their energies far away from Pannonia, so at least for a while he could be assured that they will not attack him. And of course he may have hoped that these two dangerous neighbours would weaken each other.
Prelude.
Hungarian armies had never been to Italy before. Military intelligence was one of the most important features of nomadic warfare. Starting a war without knowing the enemies power, number of soldiers, will to fight, etc., was unimaginable in the nomadic societies. This is why in late October 898 they sent a light armored, quick moving small unit on reconnaissance, which crossed Pannonia on their way to Northern Italy, then arrived in Italy in Friuli. They camped three days with their tents near the river Brenta, sending their scouts in small groups to reconnoitre the land, its wealth, the number and the fighting spirit of the enemy troops, the routes of attack and retreat, the places which can be chosen as battlefields, where the most spoils are to find, the number of the cities, castles and the strength of their defence system. It is certain that the place of the future battle was chosen during this minor incursion. We do not know the exact numbers of this scout unit, but according to Marco Polo, in the Mongolian Empire the reconnaissance units were composed of 200 riders. So we can presume that the Hungarian scout unit, which went in 898 into Italy, had a number around 100-200. After three days the small groups they sent in every direction, returned, analyzed the information they gained, then returned home.
As Liutprand of Cremona mentions, after returning home, the Hungarians used the winter to prepare their weapons, sharpen their arrowheads, and to teach to the youth how to fight. Then in 899, a Hungarian army, crossing Pannonia, headed to Italy. The historians do not agree about the road they took. Gyula Kristó argues that they bypassed Pannonia, and went westwards following the courses of the rivers Sava and Drava, and entering Italy near Aquileia, on the road named after them "Strata Hungarorum", due to the fact that they used it so often during the next decades and centuries. According to István Bóna, the Hungarian army, with the permission of Arnulf, crossed Pannonia, then headed towards Italy on the ancient road Via Gemina, which linked the ancient cities Celeia, Ljubljana and Aquileia, arrived in Italy. The historians' opinions differ also about the period of the year in which the Hungarian army arrived to Italy. According to Kristó, basing on the account of Liutprand, they arrived in February–March. Bóna believes, according to the account of "Catalogus abbatum nonantulorum" that they arrived in August 899.
They entered Italy they passed next to the big walls of Aquileia, without attacking it, then scattered in smaller units, spread in many directions, attacking the surroundings of Treviso, Vicenza, Verona, Brescia, Bergamo, Milano, Pavia, destroying Feltre, one of their unit reaching in the West even the Great St Bernard Pass. Usually the Hungarian nomadic warriors did not attack the castles and big cities surrounded by walls, because they were not skilled in sieges, and having no siege machinery, so they plundered and burned monasteries, gathering spoils in the way.
As Liutprand of Cremona mentions, hearing about the apparition of the Hungarians in his kingdom, Berengar I. was very surprised how this army from a nation, about which he never heard of, appeared so suddenly. Then he sent envoys and letters in every corners of his country demanding to everybody to send their troops to him to fight the Hungarians. After all his troops gathered his army became three times bigger than the Magyar army. According to "Chronicon Sagornini" of John the Deacon, the Italian army was 15,000, so we can conclude, that the Hungarians were 5,000. This number could be exaggerated, like the medieval chroniclers often did with the numbers of the armies, but the affirmation that the Italians were three times more than the Hungarians, has no reason not to be accepted, because usually the chroniclers exaggerate the number of the enemy armies and diminish the number of the troops of their own, so we can accept that the Italians heavily outnumbered the Hungarians. Noticing his superiority, Berengar started to think too much of himself, and instead of attacking the Hungarian army immediately, he spent his time in a town carousing with his men. This gave time to the Hungarian troops, scattered to plunder in every corner of the Italian kingdom, to retreat towards the gathering place, one precisely not specified place on the bank of the river Brenta, which, as shown before, probably was chosen from the beginning to be the place of the battle. Seeing this, king Berengar thought that they were frightened from the number of his troops, and started to chase them, thinking that he already won. His mounted troops even managed to surprise a Hungarian troop and force it to cross in haste the river Adda causing the drowning of many of them. But generally the retreat was a success, because the Hungarians light armors and weapons (the commoners, who usually made the pillaging raids, wear no or just leather armours, only the leaders had lamellar armours, their weapons were always composite bows, the hand-to-hand weapons were sabres, and rarely battle axes or maces) enabled their horses to be more rapid than the heavy armored and weaponed Carolingian type Italian cavalry. The Hungarians retreated on the old Roman road Via Postumia towards the future battlefield.
The Hungarians retreat also served as was part of their psychological warfare, which had the goal to induce self-confidence in Berengar and the belief that he already won the war against them, with this lulling his vigilance. To augment this they sent envoys to Berengar, which promised that they will renounce to all of their plunders, and asked only their safe return to their homeland, but the over confident Berengar and his commanders refused this, believing that it will be an easy task to make them all prisoners. Although the chronicler Liutprand believes that the Hungarians were frightened, hopeless, and just wanted to escape alive, but the modern historians realized that this was only a clever role playing in order to induce the Italians in the mood, which eased their future defeat. The role playing of the Hungarian army was almost exposed when the Italian vanguard reached the Hungarian rearguard at the "wide fields" of Verona and forced it to fight, and the Magyars were forced to defeat the Italians, in order to escape, although probably it was not among the commanders' plans to expose their strength before the final battle. But when Berengar's main forces arrived, the Hungarian rearguard ran away, continuing its retreat. But Berengar did not took this sign too serious, and continued to chase the fleeing Hungarians.
After this long pursuit, on 24 September 899, the Hungarians and the Italians arrived to the river Brenta, after the "most ingenious planned flight of the world history", as István Bóna points. He probably names this retreat so, because of the multiple results it produced: 
The nomadic armies used the tactic of feigned retreat very often in the ancient and medieval times, and the Hungarians were masters of it, using it in many battles of the period of their invasions of Europe (899-970). Liutprand mentions that the horses of the Hungarians were very tired, but they had the strength to cross the river before the Italians arrived, so Brenta separated the two armies from each other. The heavily armored Italians could not pass the river so easily, so they remained on the other side, and both armies assembled their battle lines on the both sides of the river.
Then the Hungarians again sent envoys to the Italian side, this time with even more alluring propositions for the Italians; in return for their safe return home, they promised to give them everything: prisoners, equipment, weapons, horses, keeping only one for each of them for their homecoming. To show how serious they are about this proposal, they promised that they will never return to Italy, and as guarantees for this, they will send their own sons to the Italians. With these exaggerate but still unacceptable promises (knowing that Berengar will not accept their departure after the destruction they caused, and would want to take them all prisoners), the Hungarians managed to totally convince the king that their fate depends only from his goodwill. So the Italians responded harshly, threatening them, probably wanting their total surrender.
The Hungarians waited for this moment. The Italians assembled a fortified camp, which however was not sufficiently guarded, left their guard down, and many of them started to eat and drink, to refresh after the long and exhausting pursuit, waiting the continuation of the negotiations, because Berengar thought that the Magyars are too weak and tired to fight, so they are at his mercy. But at the other side of the Brenta river was probably not only the tired, pursued Magyar army group, but other Hungarian troops too which at the start of the campaign, were sent in other directions to plunder, and in the meantime they returned for the battle, and also those who remained in their permanent camp placed in that very place from the beginning of the campaign, because it was chosen a year ago in their reconnaissance incursion. In their campaigns in Europe, the Hungarians in every country they stayed longer, chose a place to be their permanent camp during their stay in the region (in 926 the Abbey of Saint Gall, in 937 in France the Abbey of Saint Basolus near Verzy, in the same year the meadows of Galliano near Capua, where they stood for 12 days), so knowing these, it is highly probable, that the principal camp and the rallying point of the Hungarians was on the meadows near the Brenta river. So, without Berengar's knowledge, on the other side of the river were a great number of fresh troops with fresh horses, which just waited to start the battle.
Battle.
When the Italians were totally unaware and relaxed, the Hungarians sent three troops to cross the river on some remote places, and to place themselves on different strategical points around the Italian camp. When these units took their places, the main Hungarian army crossed the river, at an area away from the detection of the Italians, and directly charged the unsuspecting Italians outside the camp, starting a massacre among them.
The majority of the Italians were in the fortified camp, eating and drinking, when the three Hungarian units sent in ambush, encircled the camp and started to shoot arrows, and caught the Italians so off guard, that Liutprand writes that many of them still ate in the moment, when the Hungarians arrows, or lances pierced the food in their throats. Of course, Liutprand could be exaggerating when he writes that the Italians were killed with the food in their throats, but nevertheless he expresses with this image the total surprise caused by the Hungarian attack to the Italians. This simultaneous attack on the Italians inside and outside of the camp, prevented them from helping each other. The Hungarians who attacked the camp, destroyed the defences preventing the Italians from barricading themselves in the camp, shot continuously arrows on the Italians trapped in it, and probably waited for the main army to finish the Italians outside, then they stormed together inside the fortified camp, because the Italians, due to their surprise and terror, were in impossibility to organize a defence of it, and started a slaughter. The Italians were totally off guard, and was impossible for them to organize a resistance, being caught in this way, so the only option was to flee. But when some of them arrived to the place where their horses were camped, they saw that it was already taken by Hungarian warriors, so these Italians were massacred by them. Probably one of the three Hungarian units sent before to encircle the Italian camp had the duty to occupy the stables before the battle even started.
Some Italians tried to stay away from the little pockets of fight, where groups of their fellows tried to resist, hoping that if they show themselves peaceful and friends to the Hungarians, they will be spared, but they too were massacred.
The Hungarians, after crushing all tiny attempts of resistance, showed no mercy to the Italians, who in the course of the days spent in chasing them, then after their arriving to the Brenta river, when they sent their envoys asking for an agreement, insulted them so many times, so they killed even those who wanted to surrender.
The number of the Italian losses was huge. Annales Fuldenses show the number of the Italians killed as 20,000 men. This is of course an exaggerated number, knowing that the Italian army composed maximum 15,000 men, but shows that the losses were really high. "Catalogus abbatum nonantulorum" writes about thousands of Christian deaths, the "Chronicon" of Regino of Prüm writes about the uncountable masses of the people killed with arrows, or "Chronicon Sagornini" of John the Deacon points that "few of them [the Italians] turned back home". The Hungarian losses were low, since they encountered almost no resistance.
King Berengar managed to escape to Pavia, changing his dress with the clothing of one of his soldiers.
This battle is a vivid example of the ingenuity and the multitude of methods and strategies which the armies of the nomadic societies used in order to achieve victory including choosing the right battlefield which assured superiority over the enemy days or weeks before the battle, deceiving military moves, psychological warfare, the importance of surprise attacks and preponderance of archery in the battle.
Aftermath.
After this victory the whole Italian Kingdom lied on the mercy of the Hungarians. With no Italian army to oppose them, the Hungarians decided to spend the mild winter in Italy, continuing to attack monasteries, castles and cities, trying to conquer them, like they did before they had started to be chased by Berengar's army.
On 13 December 899 they attacked Vercelli, where the bishop of Vercelli and archchancellor of the Carolingian Empire, Liutward, trying to escape them, taking with him his treasures, accidentally stumbled upon them, so he was killed and his treasures taken away. On 26 January 900 they conquered Modena, and two days later the Abbey of Nonantola, where they burned the monastery and the church, and killed monks.
In the meantime, on 8 December 899, emperor Arnulf died in Regensburg, so the alliance between East Francia and the Principality of Hungary lost its validity. The Hungarian envoys sent from the new home of the Hungarians, the eastern part of the Carpathian Basin, to negotiate the renewal of the alliance, were seen as spies by the guardian and councillor of the new king, the 6 year old Louis the Child, Hatto I, Archbishop of Mainz and his advisers, and sent home, having achieved nothing. This started a state of war between the two political communities, so the Principality of Hungary needed the Hungarian army from Italy, which, because they became an important task in the conquest of Pannonia, which was planned by the Hungarians. They had to attack the Bavarian province from South West in the same time when another Hungarian army attacked it from East.
Before the Hungarians left Italy, in the spring of 900, they concluded peace with Berengar, who gave them in exchange for they departure hostages, and money for the peace. After this defeat, or at the latest from 904, Berengar started to pay them tribute regularly, and until his death in 924, and in exchange the Hungarians helped him against every enemies that he had. As Liuprand writes, the Hungarians became Berengar's friends. It seems that, in time, some of the Hungarian leaders became his personal friends.
On their way back home, the Hungarians accomplished a military performance, which was never even tried by a land army in the history. Having no ships, boats or any kind of watercraft, on 29 June 900, they "embarked" on a sea campaign against Venice. As "Chronicon Sagornini" of John the Deacon writes that with their horses and "leather ships" to attack first the cities from the coast, then also the city of Venice itself. The "leather ship" here refer to an animal skin (goat, sheep, maybe cow) tied up to form something like a huge bota bag, filled with air, tied on their horses sides, which helped the warrior and his horse to float, with which the Hungarians and the warriors of other nomadic societies usually used to cross rivers. They first attacked and burned the coastal towns like Equilio, Cittanova, Fine, Capo d'Argine, then tying the filled animal skins to their horses, they crossed the waters of the Lagoon of Venice, and sacked the island town of Chioggia, which was a part of the Dogado (homeland of the Republic of Venice). Then on the day of the martyrdom of Saint Peter and Saint Paul (29 June), on their "leather ships", they tried to enter Rialto and Malamocco, but before they reached the islands, on the place called Albiola the doge of Venice Pietro Tribuno met them with the Venetian war fleet, forcing them to retreat. Although they lost this unusual sea battle, the Hungarians achieved something what was never done by a land army: attacking islands lying in the sea. And although the attack from 29 June was unsuccessful, they succeeded in the attack on the island of Chioggia. This attack was not a violation of the agreement with Berengar, because at that time Venice was not part of the Italian kingdom, but was an autonomous republic under Byzantine influence.
Historians disagree about the route taken by which the army returned to the Hungarian lands. On one hand György Szabados believes that the Hungarian army turned back home from Italy without entering Pannonia, avoiding it from the south, because in his opinion they were exhausted of continuous fighting in Italy in the last year, and were loaded up with plunders, so they would not be capable to accomplish such an important mission. The same opinion had György Györffy too in 1974.
On the other hand, Gyula Kristó and István Bóna think that the Hungarian army returning from Italy took part in the conquest of Pannonia, but in different ways. Kristó believes that the returning Hungarian army had the task only to plunder the land, weakening the capability of the inhabitants to withstand the final attack, then crossed the Danube, turning home, and after that two new Hungarian armies, coming from East accomplished the occupation. Bóna believes that the returning Hungarian army played an active role in the conquest of Pannonia, coming from the southwest, when other armies coming from east, from the Eastern part of the Carpathian Basin, crossed the Danube, attacking it from the north and east. He thinks that the Hungarian army came back from Italy because they received an order from home to come help in the conquering of Pannonia, accomplishing it with an encircling movement.