The young king Sebastian I was burning with zeal to go to Morocco and stop the advances of the Turkish-supported armies, an enterprise which held the promise of more land and revenues in North Africa for the nobles (they perhaps believing this would allow them to maintain their economic supremacy over the merchants), but the mercantile bourgeoisie also supported the effort as it would benefit Portuguese commerce in North Africa. Sebastian used much of Portugal's imperial wealth to equip a large fleet and gather an army. He and the flower of the Portuguese nobility were killed in the military disaster of the Battle of Alcácer Quibir in 1578, his death triggering a succession crisis, where the main claimants to the throne were Philip II of Spain and António, Prior of Crato. The remaining Portuguese nobles and the high clergy were gathered once again to the arms of their like-minded counterparts, the Castilians, and supported Philip, a maternal grandson of Manuel I of Portugal. Philip sent an army of 40,000 men under the command of the Duke of Alba to invade Portugal. They defeated António's troops at the Battle of Alcântara and Philip was crowned Philip I of Portugal in 1581. Thus he at least partly fulfilled the ambition of his father, the Habsburg King Carlos I of Spain (also Charles V of the Holy Roman Empire), who was famously quoted by Friar Nicolau de Oliveira: "Se eu fora Rei de Lisboa eu o fora em pouco tempo de todo o mundo" ("If I were King of Lisbon, I would soon rule over all the world.") The union of Portugal with Spain lasted sixty years (1580–1640).