during krešimir's reign, the normans from southern italy first became involved in balkan politics and krešimir soon came in contact with them. after the 1071 battle of manzikert, where the seljuk turks routed the eastern imperial army, the diocleans, serbs and other slavs instigated a rebellion of boyars in macedonia and in 1072, krešimir is alleged to have lent his aid to this uprising. in 1075, the normans under peter ii of trani invaded the dalmatian possessions of croatia from southern italy, most likely at the command of the pope, who had been in a quarrel with the king of croatia over papal politics towards his kingdom. during the invasion, the norman count amico of giovinazzo besieged the island of rab for almost a month (14 april to early may). he failed in his siege of rab, but he managed to take the island of cres on 9 may. it was during these clashes that the croatian king himself was captured by amico at an unidentified location. in return for liberation, he was forced to relinquish many cities, including both his capitals, as well as zadar, split, and trogir. his followers, such as the bishop of cres, also collected a large ransom. however, he was not liberated. over the next two years, the republic of venice expelled the normans and secured the cities for themselves.