Charles's victory at the Battle of Pavia (1525) surprised many Italians and Germans and elicited concerns that Charles would endeavor to gain even greater power. Pope Clement VII switched sides and now joined forces with France and prominent Italian states against the Habsburg Emperor, in the War of the League of Cognac. In 1527, due to Charles' inability to pay them sufficiently, his armies in Northern Italy mutinied and sacked Rome itself for loot, forcing Clement, and succeeding popes, to be considerably more prudent in their dealings with secular authorities: in 1533, Clement's refusal to annul Henry VIII of England's marriage to Catherine of Aragon (Charles' aunt) was a direct consequence of his unwillingness to offend the emperor and perhaps have his capital sacked a second time. The Peace of Barcelona, signed between Charles and the pope in 1529, established a more cordial relationship between the two leaders that effectively named Spain as the protector of the Catholic cause and recognized Charles as king of Lombardy in return for Spanish intervention in overthrowing the rebellious Florentine Republic.