The War of the Portuguese Succession, a result of the extinction of the Portuguese royal line after the Battle of Alcácer Quibir and the ensuing Portuguese succession crisis of 1580, was fought from 1580 to 1583 between the two main claimants to the Portuguese throne: António, Prior of Crato, proclaimed in several towns as King of Portugal, and his first cousin Philip II of Spain, who eventually succeeded in claiming the crown, reigning as Philip I of Portugal. Wikipedia