The War of the Castilian Succession was the military conflict contested from 1475 to 1479 for the succession of the Crown of Castile fought between the supporters of Joanna 'la Beltraneja', reputed daughter of the late monarch Henry IV of Castile, and those of Henry's half-sister, Isabella, who was ultimately successful.
The war had a marked international character, as Isabella was married to Ferdinand, heir apparent to the Crown of Aragon, while Joanna was strategically married to King Afonso V of Portugal, her uncle, after the suggestion of her supporters. France intervened in support of Portugal, as they were rivals with Aragon for territory in Italy and Roussillon.