Archons". In 1143, George founded the Greek Orthodox church of S. Maria dell'Ammiraglio, also known as the Martorana, in Palermo. In the church there is a contemporary mosaic depicting George, as well as a mosaic showing Roger II being crowned by Christ. Height of career: conquests in Greece and Africa In 1146, George captured Tripoli and established Sicilian authority in North Africa on a permanent basis. He had already captured several minor coastal cities in the fifteen years prior, but Mahdia, which had been in the hands of Abul-Hasan al-Hasan ibn Ali since the failed attack of 1123, did not capitulate yet. In 1147, Roger attacked the Byzantine Empire, which continued to contest his gains in southern Italy. George he sent from Otranto with seventy galleys to assault Corfu. According to Nicetas Choniates, the island capitulated due to the imperial tax burden and George's promises. Leaving a garrison, George sailed on to the Peloponnesus. He sacked Athens and quickly moved on to the Ionian Islands. He ravaged the coast all along Euboea and the Gulf of Corinth and penetrated as far as Thebes, where he pillaged the silk factories and carried off the Jewish silk weavers. George capped the expedition with a sack of Corinth, in which the relics of Saint Theodore were stolen, and then returned to Sicily. In 1148, George finally conquered Mahdia. Antecedently, the governor of Gabès had revolted against his overlord, al-Hasan, and promised to deliver his city to Roger II if he was confirmed as governor. War inevitably broke out in the summer of 1148. George led a fleet against Mahdia. The sultan voluntarily went into exile, taking with him very little treasure, and Mahdia capitulated. The cities of Sfax and Soussa surrendered soon after. Tunisia (Ifriqiya) was incorporated into the Kingdom of Sicily, which reached its apogee through George's conquests, containing not only Sicily and the Mezzogiorno, but also Corfu and Tunisia. In 1149, Corfu was retaken and George took a fleet of forty ships up the Bosphorus to the walls of Constantinople, where he tried to land. Failing this, he ravaged a few villae on the Asian coast and fired arrows at the imperial palace. He died soon after, in year 546 AH according to Ibn al-Athir, corresponding to 1151 or 1152. He was succeeded in his offices by Philip of Mahdia. George was a polyglot and very cultured man. He founded the