Siege of Berat ( 1280 – 81 ) The Siege of Berat in Albania by the forces of the Angevin Kingdom of Sicily against the Byzantine garrison of the city took place in 1280 – 1281 . Berat was a strategically important fortress , whose possession would allow the Angevins access to the heartlands of the Byzantine Empire . A Byzantine relief force arrived in spring 1281 , and managed to ambush and capture the Angevin commander , Hugo de Sully . Thereupon , the Angevin army panicked and fled , suffering heavy losses in killed and wounded as it was attacked by the Byzantines . This defeat ended the threat of a land invasion of the Byzantine Empire , and along with the Sicilian Vespers marked the end of the Western threat to reconquer Byzantium . Background . Ever since the Emperor Michael VIII Palaiologos ( r . 1259 – 1282 ) recovered Constantinople from the Latin Empire in 1261 , the restored Byzantine Empire faced the threat of a Latin crusade to reclaim the city . The antagonistic Greek Despotate of Epirus and the Latin states of southern Greece , fearful of the Byzantine resurgence , sought aid from the Kingdom of Sicily , first under Manfred of Sicily ( r . 1258 – 1266 ) , and after 1266 under the ambitious Charles of Anjou ( r . 1266 – 1285 ) , who quickly established himself as Byzantium ' s chief antagonist . Countering the Angevin ruler ' s alliances and efforts to conquer Byzantium would occupy the remainder of Michael VIII ' s reign . In 1258 , the Sicilians took possession of the island of Corfu and the Albanian coast , from Dyrrhachium to Valona and Buthrotum and as far inland as Berat . This gave Manfred a strategically vital beachhead in the Balkans , controlling the western terminus of the great Via Egnatia , the main overland route to Constantinople . Already in the 11th and 12th centuries , the same area had been the target of the Normans of southern Italy in their attacks on the Empire . After overthrowing Manfred , in the Treaty of Viterbo ( 1267 ) Charles secured his recognition as Manfred ' s heir . In 1272 , the Latin notables who had held the fortresses of Valona , Kanina , and Berat for Manfred surrendered them to Charles , and soon afterwards Charles ' s troops took Dyrrhachium too . Having secured the support of many Albanian chieftains , Charles proclaimed the establishment of the Kingdom of Albania in the same year . Michael VIII countered the emerging threat by a diplomatic mission to the Papacy , which in the Second Council of Lyon ( 1274 ) agreed to the union of the Orthodox and Catholic churches , estranged after the Great Schism of 1054 , and thereby placed Michael and his empire under papal protection . Taking advantage of Charles ' s entanglement in the conflict between Guelphs and Ghibellines in Italy , in spring 1274 Michael launched an attack against Angevin holdings in Albania . Berat and Buthrotum were taken and Charles ' s troops were pushed back from the hinterland to the two ports of Valona and Dyrrhachium . Although these were assaulted several times in 1274 – 1275 , they remained in Angevin hands . By 1279 however , Charles had established his control not only over the Latin states of Greece ( after 1278 he was the Prince of Achaea ) , but also received the submission and vassalage of Nikephoros I , Despot of Epirus . In August 1279 , in preparation for resuming his offensive against Michael along the Via Egnatia , Charles appointed as his vicar - general in Albania the Burgundian Hugo de Sully . Over the next year , Sully received a steady flow of supplies , siege equipment and reinforcements . The siege . In August / September 1280 , with an army of 2 , 000 knights and 6 , 000 infantry , Sully began his attack by storming the fortress of Kanina and then advancing to central Albania and laying siege to Berat . The situation was grave for Byzantium : Berat was , in the words of the historian Deno J . Geanakoplos " the key to the Via Egnatia and all of Macedonia " . If it were taken , the Empire would lie open to an invasion , which , if joined by the Latin states of Greece and the Greek rulers of Epirus and Thessaly , might result in the fall of Constantinople to Charles . Responding to the pleas for reinforcements of the governor of Berat , Michael VIII ordered special prayers for the salvation of the Empire , and assembled an army headed by some of his best generals . The army ' s commander - in - chief was the " megas domestikos " Michael Tarchaneiotes , with the " megas stratopedarches " John Synadenos , the " despotes " Michael Komnenos Doukas ( the emperor ' s son - in - law ) , and the eunuch court official Andronikos Enopolites as subordinate commanders . Meanwhile , the siege of Berat continued through the winter of 1280 / 1281 . By early December , the Angevin forces had seized a number of outlying forts around the city and penetrated its suburbs . Charles , however , remained anxious to take the city before the Byzantine relief force arrived . He ordered his governors in Albania to direct all their resources towards the siege , and displayed his close interest by a series of letters to Sully , instructing him to take the city by assault if necessary . The Byzantine force advanced cautiously , and arrived in the area in early spring 1281 . The " megas domestikos " Tarchaneiotes avoided a direct confrontation and relied on ambushes and raids instead . He also managed to resupply the besieged fortress with provisions , which were loaded onto rafts and then left to float down the river Osum which flows by the citadel . The besiegers became aware of this , and , unlike the Byzantines , the Angevin commanders were eager for a decisive confrontation . At this point , Sully resolved to reconnoitre the area personally , accompanied only by a bodyguard of 25 men . As he approached the Byzantine camp , he fell into an ambush by Turkish mercenaries serving in the Byzantine army . The Turks attacked the small troop , killed Sully ' s horse , scattered his guard , and captured him . A few of Sully ' s guards escaped and reached their camp , where they reported his capture . Panic spread among the Angevin troops at this news , and they began to flee towards Valona . The Byzantines took advantage of their disordered flight and attacked , joined by the troops in the besieged citadel . Many Latins fell , many others were captured as the Byzantines aimed their arrows at the less well - protected horses of the Latin knights , unhorsing them . The Byzantines also took an enormous booty , including all the numerous siege machines . Only a small remnant managed to cross the river Vjosë and reach the safety of Kanina . Aftermath . The victory at Berat represented Michael VIII ' s greatest success in battle over the Latins since the Battle of Pelagonia 20 years earlier . The many prisoners , including Sully , were taken to Constantinople , where they were publicly paraded in a triumph celebrated by the exultant emperor , who further ordered frescoes depicting scenes from the campaign painted in his palace . In the aftermath of their victory at Berat , the imperial troops restored their control of Albania except the two Angevin strongholds of Dyrrhachium and Valona . The defeat ended Charles ' s designs of an overland assault on Byzantium , but the Angevin ruler now redoubled his efforts , aiming to launch a seaborne invasion of the Empire with Venetian aid . This he secured with the Treaty of Orvieto in 1281 . The Papacy also , after the election of the pro - Angevin Martin IV , finally sanctioned his plans , excommunicating Michael Palaiologos and ending the Union of the Churches . Michael VIII countered this with an alliance with Peter III of Aragon ( r . 1276 – 1285 ) , and with his support to various anti - Angevin forces in Italy . Just as Charles was ready to launch his attack , an uprising known as the Sicilian Vespers broke out on March 30 , 1282 . The subsequent wars , in large part the result of Michael ' s diplomatic efforts , ended the Angevin threat on Byzantium for good .