From his early years, Charles of Valois dreamed of more and sought all his life for a crown he never obtained. Starting in 1284, Pope Martin IV recognized him as King of Aragon (under the vassalage of the Holy See), as the son of his mother, Isabella of Aragon, in opposition to King Peter III of Aragon, who after the conquest of the island of Sicily was an enemy of the Papacy. Charles hence married Margaret, the daughter of the Neapolitan king, in order to re-enforce his position in Sicily which was supported by the Pope. Thanks to this Aragonese Crusade undertaken by his father King Philip III against the advice of his elder brother Philip the Fair, he believed he would win a kingdom and however won nothing but the ridicule of having been crowned with a cardinal's hat in 1285, which gave him the alias of the "King of the Cap." He would never dare to use the royal seal which was made on this occasion and had to renounce the title.