The Aragonese Crusade or Crusade of Aragon, a part of the larger War of the Sicilian Vespers, was declared by Pope Martin IV against the King of Aragon, Peter III the Great, in 1284 and 1285. Because of the recent conquest of Sicily by Peter, the Pope declared a crusade against him and officially deposed him as king, on the grounds that Sicily was a papal fief: Peter's grandfather and namesake, Peter II, had surrendered the kingdom as a fief to the Holy See. Martin bestowed it on Charles, Count of Valois, son of the French king, Philip III, and nephew of Peter III.