Treaty of Alcáçovas (1479)

The Treaty of Alcáçovas, signed on 4 September 1479, ended the War of the Castilian Succession. It recognized Isabella and Ferdinand as sovereigns of Castile and granted Portugal hegemony in the Atlantic, while ceding the Canary Islands to Castile.

Episodes

Background and detail

Background. The conflict arose from the succession dispute in Castile between Isabella and Joanna 'la Beltraneja'. Joanna was supported by her husband, Afonso V of Portugal, leading to a four-year war involving land battles and naval engagements in the Atlantic.

Negotiations. Following the indecisive Battle of Toro in 1476 and the Portuguese naval victory at Guinea in 1478, peace talks began in April 1479. These discussions, organized by Beatrice, daughter of Afonso V, led to the final agreement in Alcáçovas.

Terms. The treaty required mutual renunciation of claims to each other's thrones. Portugal gained free rein for exploration along the African coast, while Castile secured sovereignty over the Canary Islands. This established distinct spheres of control in the Atlantic.

Ratification. Afonso V ratified the agreement on 8 September 1479. The Catholic Monarchs ratified it in Toledo on 6 March 1480. The treaty was later confirmed by the papal bull Aeterni regis in 1481, solidifying the colonial boundaries.

People involved

Sources

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