Battle of Dyrrhachium (1081)

The Normans first arrived in Southern Italy in 1015 from northern France and served local Lombard lords as mercenaries against the Byzantine Empire.[6] As they were paid with lands, soon they were powerful enough to challenge Papal authority; in 1054, they defeated the Pope at the Battle of Civitate, forcing him to acknowledge their authority.[7] In 1059, the Pope made Robert Guiscard, of the Hauteville family, Duke of Apulia, Calabria, and Sicily. However, most of Apulia and Calabria were in Byzantine hands, and Sicily was in Saracen hands.[8]

By 1071, Robert, together with his brother Roger, had taken over the last Byzantine stronghold in Italy, Bari. By the next year, they conquered all of Sicily, ending the Islamic Emirate of Sicily. In 1074, the Byzantine Emperor Michael VII sent an envoy to Robert offering the hand of his son Constantine to Robert's daughter Helena.[9] Guiscard accepted the offer and sent his daughter to Constantinople. However, in 1078, Michael was overthrown by Nicephorus Botaneiates, an event that destroyed any chances Helena had for the throne.[10] This gave Robert a motive to invade the empire claiming his daughter had been mistreated; however, his intervention was delayed by a revolt in Italy.[11]

Robert conscripted all men of a fighting age into the army, which he refitted.[12] Meanwhile, he sent an ambassador to the Byzantine court with orders to demand proper treatment for Helena and to win over the Domestic of the Schools, Alexios.[13] The results of these attempts remain unknown, but the ambassador fell under Alexios's charm and as he was returning to Italy, he heard of Alexios's successful coup against Botaneiates,[12] by which he became Alexios I Komnenos.

When the ambassador returned, he urged Robert to make peace, claiming that Alexios wanted nothing but friendship with the Normans. Robert had no intention of peace; he sent his son Bohemond with an advance force towards Greece and Bohemond landed at Aulon, with Robert following shortly after.[14]

The Norman fleet of 150 ships including 60 horse transports set off towards the Byzantine Empire at the end of May 1081. The army numbered 15,000 men, including about 1,300 Norman knights.[3] The fleet sailed to Avalona in Byzantine territory; they were joined by several ships from Ragusa, a republic in the Balkans who were enemies of the Byzantines.[16]

Robert soon left Avalona and sailed to the island of Corfu, which surrendered because of a small garrison. Having won a bridgehead and a clear path for reinforcements from Italy, he advanced on the city of Dyrrhachium, the capital and chief port of Illyria.[17] The city was well defended on a long, narrow peninsula running parallel to the coast, but separated by marshlands. Guiscard brought his army onto the peninsula and pitched camp outside the city walls.[18] However, as Robert's fleet sailed to Dyrrhachium, it was hit by a storm and lost several ships.[16]

Meanwhile, when Alexios heard that the Normans were preparing to invade Byzantine territory, he sent an ambassador to the Doge of Venice, Domenico Selvo, requesting aid and offering trading rights in return.[16] The Doge, alarmed by Norman control of the Strait of Otranto, took command of the Venetian fleet and sailed at once, surprising the Norman fleet under the command of Bohemond as night was falling. The Normans counter-attacked tenaciously, but their inexperience in naval combat betrayed them. The experienced Venetian navy attacked in a close formation known as "sea harbour" and together with their use of Greek fire "bombs", the Norman line scattered, and the Venetian fleet sailed into Dyrrhachium's harbour.[19]

Coin of Robert Guiscard.

Robert was not discouraged by this naval defeat, and began his siege of Dyrrhachium. In command of the garrison at Dyrrhachium was the experienced general George Palaiologos, sent by Alexios with orders to hold out at all costs while Alexios himself mustered an army to relieve the city.[20]

Meanwhile, a Byzantine fleet arrived and – after joining with the Venetian fleet – attacked the Norman fleet, which was again routed. The garrison at Dyrrhachium managed to hold out all summer, despite Robert's catapults, ballistae and siege tower. The garrison made continuous sallies from the city; on one occasion, Palaiologos fought all day with an arrowhead in his skull. Another sally succeeded in destroying Robert's siege tower.[20]

Robert's camp was struck by disease; according to contemporary historian Anna Comnena up to 10,000 men died, including 500 knights.[21] Even so, the situation of the Dyrrhachium garrison grew desperate because of the effects of Norman siege weapons. Alexios learned of this while he was in Salonica with his army so he advanced in full force against the Normans. According to Comnena, Alexios had about 20,000 men; historian John Haldon puts the army's size between 18,000 and 20,000 men, while John Birkenmeier estimates it between 20–25,000 men. It consisted of Thracian and Macedonian tagmata, which numbered about 5,000 men; the elite excubitors and vestiaritai units, which numbered around 1,000 men; a force of Manichaeans which comprised 2,800 men, Thessalian cavalry, Balkan conscripts, Armenian infantry and other light troops. As well as the native troops, the Byzantines were joined by 2,000 Turkish and 1,000 Frankish mercenaries, about 1,000 Varangians and 7,000 Turkish auxiliaries sent by the Seljuk Sultanate of Rûm. Alexios also withdrew the tagmas from Heraclea Pontica and the remaining Byzantine holdings in Asia Minor and by doing so, he effectively left them to be overrun by the Turks.[19]

The battle was a heavy defeat for Alexios. Historian Jonathan Harris states that the defeat was "every bit as severe as that at Manzikert."[26] He lost about 5,000 of his men, including most of the Varangians. Norman losses are unknown, but John Haldon claims they are substantial as both wings broke and fled.[4] Historian Robert Holmes states: "The new knightly tactic of charging with the lance couched – tucked firmly under the arm to unite the impact of man and horse – proved a battle-winner."[27]

George Palaiologos had not been able to re-enter the city after the battle and left with the main force. The defense of the citadel was left to the Venetians, while the city itself was left to the Count of the Tent mobilizing from Arbanon (ἐξ Ἀρβάνων ὁρμωμένω Κομισκόρτη).[28][29]

In February 1082, Dyrrhachium fell after a Venetian or Amalfian citizen opened the gates to the Normans.[30] The Norman army proceeded to take most of northern Greece without facing much resistance. While Guiscard was in Kastoria, messengers arrived from Italy, bearing news that Apulia, Calabria, and Campania were in revolt. He also learned that the Holy Roman Emperor, Henry IV, was at the gates of Rome and besieging Pope Gregory VII, a Norman ally.[31] Alexios had negotiated with Henry and given him 360,000 gold pieces in return for an alliance. Henry responded by invading Italy and attacking the Pope. Guiscard rushed to Italy, leaving Bohemond in command of the army in Greece.[32]

Alexios, desperate for money, ordered the confiscation of all the church's treasure.[33] With this money, Alexios mustered an army near Thessalonica and went to fight Bohemond. However, Bohemond defeated Alexios in two battles: one near Arta and the other near Ioannina. This left Bohemond in control of Macedonia and nearly all of Thessaly.[34] Bohemond advanced with his army against the city of Larissa. Meanwhile, Alexios had mustered a new army and with 7,000 Seljuk Turks sent by the Sultan, he advanced on the Normans at Larissa and defeated them.[35] The demoralised and unpaid Norman army returned to the coast and sailed back to Italy.[36] Meanwhile, Alexios granted the Venetians a commercial colony in Constantinople, as well as exemption from trading duties in return for their renewed aid. They responded by recapturing Dyrrhachium and Corfu and returning them to the Byzantine Empire. These victories returned the Empire to its previous status quo and marked the beginning of the Komnenian restoration.[37]