Before Philip II of Spain had a chance to enforce his claim to the crown of Portugal, in 1580, António, Prior of Crato, an illegitimate scion of the Beja line of the House of Braganza Portuguese Royal Family, proclaimed himself king on 24 July 1580. However, his rule in continental Portugal lasted only twenty days; on 25 August, he was defeated at the Battle of Alcântara by the Spanish Habsburg armies led by Fernando Álvarez de Toledo, Duke of Alba.