Castilian War of Succession

War of the Castilian Succession
Left, Isabella I of Castile. Right, Joanna la Beltraneja
Date 1475–1479 Location Crown of Castile and Atlantic Ocean Result Treaty of Alcáçovas: Isabella is recognised as Queen of Castile Marriage of Isabella of Aragon and Afonso of Portugal Portugal gains hegemony in the Atlantic south of the Canary Islands Portugal recognizes Castile's claim to the Canary Islands
Belligerents
Isabella Supporters Crown of Aragon	Juana Supporters Kingdom of Portugal Kingdom of France
Commanders and leaders
Isabella I of Castile Pedro Gonzalez de Mendoza Beltrán de la Cueva Francisco García Pérez de Guzmán Ferdinand II of Aragon Alonso de Cárdenas Rodrigo Manrique † Jorge Manrique †	Joanna la Beltraneja Alfonso Carrillo de Acuña Diego López Pacheco Álvaro de Zúñiga Ponce de León Rodrigo Téllez Girón Afonso V of Portugal Prince John of Portugal Louis XI of France

Treaty of Alcáçovas:

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, 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 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.

Despite a few initial successes by the supporters of Joanna, a lack of military aggressiveness by Afonso V and the stalemate in the Battle of Toro (1476) led to the disintegration of Joanna's alliance and the recognition of Isabella in the Courts of Madrigal-Segovia (April–October 1476): "In 1476, immediately after the indecisive battle of Peleagonzalo [near Toro], Ferdinand and Isabella hailed the result as a great victory and called Courts at Madrigal. The newly gained prestige was used to win municipal support from their allies ..." (Marvin Lunenfeld).

The war between Castile and Portugal alone continued. This included naval warfare in the Atlantic, which became more important: a struggle for maritime access to the wealth of Guinea (gold and slaves). In 1478, the Portuguese navy defeated the Castilians in the decisive Battle of Guinea.

The war concluded in 1479 with the Treaty of Alcáçovas, which recognized Isabella and Ferdinand as sovereigns of Castile and granted Portugal hegemony in the Atlantic, with the exception of the Canary Islands. Joanna lost her right to the throne of Castile and remained in Portugal until her death.

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