In 1015 and again in 1016 forces from the taifa of Denia, in the east of Muslim Spain (al-Andalus), attacked Sardinia and attempted to establish control over it. In both these years joint expeditions from the maritime republics of Pisa and Genoa repelled the invaders. These Pisan–Genoese expeditions to Sardinia were approved and supported by the Papacy, and modern historians often see them as proto-Crusades. After their victory, the Italian cities turned on each other, and the Pisans obtained hegemony over the island at the expense of their erstwhile ally. For this reason, the Christian sources for the expedition are primarily from Pisa, which celebrated its double victory over the Muslims and the Genoese with an inscription on the walls of its Duomo.