1113 – 15 Balearic Islands expedition 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 . Treaty and preparations . In 1085 Pope Gregory VII had granted suzerainty over the Balearics to Pisa . In September 1113 a Pisan fleet making an expedition to Majorca was put off course by a storm and ended up near Blanes on the coast of Catalonia , which they initially mistook for the Balearics . The Pisans met with the Count of Barcelona in the port of Sant Feliu de Guíxols , where on 7 September they signed a treaty " causa corroborandae societatis et amicitiae " ( " for the cause of social cooperation and friendship " ) . Specifically the Pisans were exempted from the " usagium " and the " jus naufragii " in all the territories , present and future , of the Count of Barcelona , though Arles and Saint - Gilles , in the recently acquired March of Provence , were singled out for special mention ( three times ) . The only surviving copy of the treaty between Pisa and Barcelona is found interpolated in a charter of James I granted to Pisa in 1233 . It affirms that the meeting was unplanned and apparently arranged by God . Some scholars have expressed doubt about the lack of preparation , citing the Catalans ' rapid response to the presence of the Pisans as evidence of some previous contact . The attribution of the meeting to Providence alone may have been concocted to add an " aura of sacredness " to the alliance and the crusade . The treaty , or what survives of it , does not refer to military cooperation or a venture against Majorca ; perhaps that agreement was oral , or perhaps its record has been lost , but a Crusade was planned for 1114 . The chief goal was the freeing of Christian captives and the suppression of Muslim piracy . Most of the Pisan fleet returned to Pisa , but some ships damaged by the storm remained to be repaired and some men remained behind to construct siege engines . In the spring of 1114 a new fleet of eighty ships arrived from Pisa , following the French coast , briefly staying at Marseille . The fleet brought with it Cardinal Bosone , an envoy from Paschal II , who vigorously supported the expedition , authorising it in a bull as early as 1113 . Paschal had also granted the Pisans the " Romana signa , sedis apostolicae vexillum " ( " Roman standard , the flag of the apostolic see " ) , and his appeals for the expedition had borne fruit . Besides the 300 ships of the Pisan contingent , there were 120 Catalan and Occitan vessels ( plus a large army ) , contingents from the Italian cities of Florence , Lucca , Pistoia , Rome , Siena , and Volterra , and from Sardinia and Corsica under Saltaro , the son of Constantine I of Logudoro . Among the Catalan princes there were Ramon Berenguer , Hug II of Empúries , and Ramon Folc II of Cardona . The most important lords of Occitania participated , with the exception of the Count of Toulouse , Alfonso Jordan : William V of Montpellier , with twenty ships ; Aimeric II of Narbonne , with twenty ships ; and Raymond I of Baux , with seven ships . Bernard Ato IV , the chief of the Trencavel family , also participated . Ramon Berenguer and his wife , Douce , borrowed 100 " morabatins " from the Ramon Guillem , the Bishop of Barcelona , to finance the expedition . Conquest and loss . The combined Crusader fleet raided Ibiza in June , and destroyed its defences , since Ibiza lay between Majorca and the mainland and would have posed a continued threat during a siege . The " Liber maiolichinus " also records the taking of captives , who were trying to hide in " careae " ( probably caves ) , on Formentera . Ibiza was under Crusader control by August . The Crusaders invested Palma de Majorca in August 1114 . As the siege dragged on the counts of Barcelona and Empúries entered into peace negotiations with the Muslim ruler of Majorca , but the cardinal and Pietro Moriconi , the Archbishop of Pisa , interfered to put an end to the discussions . Probably the Catalan rulers , whose lands lay nearest the Balearics , expected an annual payment of " parias " ( tribute ) from the Muslims and the cessation of pirate raids in return for lifting the siege . Muslim reinforcements , Almoravids from the Iberian port of Denia , surprised a Pisan flotilla of six in the waters off Ibiza , with only two of the Pisan vessels making it to safety , which consisted of the remains of a fortress burned by the king of Norway a decade earlier . In April 1115 the city capitulated and its entire population was enslaved . This victory was followed by the capture of most of the Balearics ' major settlements and the freeing of most captive Christians on the islands . The independent Muslim " taifa " ruler was taken back to Pisa a captive . The greatest victory , however , was the annihilation of Majorcan piracy . The conquest of the Balearics lasted no more than a few months . In 1116 they were reconquered by the Almoravids of peninsular Iberia .