On May 28, 1156, at the Battle at Brindisi, Norman-Sicillian King William defeated the Byzantine fleet under John Doukas and Alexios Bryennios. From the article:
"Battle of Brindisi
Background story:
The death of Roger II of Sicily in February 1154 (succeeded by William I the “Bad”), encouraged the Emperor Manuel I Komnenos to take revenge from the Normans. He sent Michael Palaiologos and John Doukas, both of whom held the high imperial rank of sebastos, with Byzantine troops, 10 Byzantine ships, and a lot of gold to invade Apulia (1155). Manuel's expedition achieved astonishingly rapid progress as the whole of southern Italy rose up in rebellion against the Sicilian Crown. Manuel had also Papal support, since the Popes were never in good terms with the unpredictable Normans of Sicily.
The city of Bari, which had been the capital of the Byzantine Catapanate of Southern Italy for centuries before the arrival of the Normans, opened its gates to the Emperor's army, and the overjoyed citizens tore down the Norman citadel. After the fall of Bari, the cities of Trani, Giovinazzo, Andria, Taranto, and Brindisi were also captured, and William who arrived with his army (which included 2,000 knights) was heavily defeated.
However, after the initial success, problems started.
The Byzantine commander Michael Palaiologos had alienated Byzantium's allies by his attitude, and this had stalled the campaign as Count Robert III of Loritello refused to speak to him. Although the two were reconciled, the campaign had lost some of its momentum: Michael was soon recalled to Constantinople, and his loss was a major blow to the campaign.
The Battle:
The turning point was the Battle of Brindisi, where the Sicilian Normans launched a major counter-attack by both land and sea. At the approach of the enemy, the mercenaries that had been hired with Manuel's gold demanded huge rises in their pay. When this was refused, they deserted. Even the local barons started to leave, and soon John Doukas was left hopelessly outnumbered. The arrival of Alexios Komnenos Bryennios with some ships did not improve the Byzantine situation. The naval battle was decided in the Sicilians' favor, while the Byzantine commanders John Doukas and Alexios Bryennios (along with 4 Byzantine ships) were captured.
William recaptured all the lands that were previously lost to Byzantines in Apulia and marched on Benevento. Pope Hadrian IV had to recognize him, and two years later Manuel made peace and withdrew from Italy.
Aftermath:
The Byzantines had to withdraw from Italy. They never came back."