War of the Castilian Succession
The War of the Castilian Succession was fought between Portugal and Castile from 1475 to 1479 over who should succeed Henry IV of Castile, his daughter, Joanna or his half-sister, Isabella. Joanna was married to Afonso V of Portugal and Isabella was wed to Ferdinand II of Aragon. Underlying this were decades-long disagreements over hegemony of the Atlantic. Both kingdoms claimed territorial sovereignty over the Canary Islands and the West Coast of Africa. While Castile had some success in land battles, Portugal had the advantage at sea.