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.