Understanding Elizabeth of Carinthia's rule in Sicily (1323–52) requires some background information specifically examining the political decision-making of Frederick III, King of Sicily and father of Elizabeth's husband Peter II. In 1282, the Crown of Aragon led by Peter III took Sicily from the Angevins, part of the outcome of the so-called Sicilian Vespers rebellion. In 1295, Pope Boniface VIII insisted that Aragon return Sicily to the Angevins. The Treaty of Anagni was signed by Peter's son James II who was king of both Sicily and Aragon at the time. The treaty promised to withdraw Aragonese troops from Sicily. Frederick III, acting governor of Sicily, however, refused to relinquish control. The Sicilians were more loyal to Frederick than the Angevins and so Frederick was crowned King of Sicily by the people at Palermo in 1296. Frederick also had the support of the local clergy, who were treated poorly by the Angevins, but Sicily had been excommunicated in 1282. Pope Boniface was not pleased about this new king of Sicily, as the Angevins were close allies to the papacy. In response, he declared successive crusades against the Sicilians in 1296, 1299, and 1302. Even with the help of Frederick's brother James, the crusading forces were not able to take back Sicily. This victory for Frederick was cemented in the treaty of Caltabellotta in 1302. The treaty recognized Frederick as the King of Sicily under the condition that his heirs must return Sicily to the Angevins upon his death in exchange for other land. It thereby allowed Sicily to remain under Aragonese rule, attracting settlers and developing trade with Catalonia. Frederick would later change his mind on these conditions, which led to Peter becoming king when he died.