The Norman expansion into southern Italy and Sicily was begun by the brothers Robert and Roger Guiscard, initially in defiance of the pope, but subsequently with his grudging cooperation. The Treaty of Melfi (1059) empowered them to take south Italy from the Greeks and Sicily from the Muslims and by the time of Roger Guiscard’s death, Sicily was in Norman hands. His son Roger II effectively ruled Sicily from 1113 but had to assert control over the anarchic Norman barons who threatened his rule, especially when backed by the pope in 1129. From 1130 Roger supported the antipope’s cause; despite excommunication by Pope Innocent II and internal revolt, he consolidated his power by 1140. He took Malta, Corfu, and many cities on the Greek mainland as well as controlling most of the land in North Africa between Tripoli and Tunis. In 1140 he issued a revised code of laws and in his later years he ruled one of the most sophisticated governments in Western Europe. His court at Palermo enjoyed a high artistic and scholarly reputation.