 Firstly, as a direct descendant of Constantine II of Cagliari he claimed that Judicate from Peter, who was ruling "jure uxoris" through Constantine's daughter.Barisone invaded Cagliari and forced Peter to flee to his brother Barisone II's court at Torres.In Spring 1164, the Judicates of Torres and Cagliari, united with the Pisans of the island, retook Cagliari and invaded Arborea.