In 1114, an expedition to the Balearic Islands, then a Muslim taifa, was launched in the form of a Crusade. Founded on a treaty of 1113 between the Republic of Pisa and Ramon Berenguer III, Count of Barcelona, the expedition had the support of Pope Paschal II and the participation of many lords of Catalonia and Occitania, as well as contingents from northern and central Italy, Sardinia, and Corsica. The Crusaders were perhaps inspired by the Norwegian king Sigurd I's attack on Formentera in 1108 or 1109 during the Norwegian Crusade. The expedition ended in 1115 in the conquest of the Balearics, but only until the next year. The main source for the event is the Pisan Liber maiolichinus, completed by 1125.. When did the Muslims regain control of the Balearic Islands?