Treaty of Alcáçovaz

The Treaty of Alcáçovas (also known as Treaty or Peace of Alcáçovas-Toledo) was signed on 4 September 1479 between the Catholic Monarchs of Castile and Aragon on one side and Afonso V and his son, Prince John of Portugal, on the other side. It put an end to the War of the Castilian Succession, which ended with a victory of the Catholic Monarchs on land and a Portuguese victory on the sea. The four peace treaties signed at Alcáçovas reflected that outcome: Isabella was recognized as Queen of Castile while Portugal reached hegemony in the Atlantic Ocean.

The treaty intended to regulate:

After Henry’s IV death in 1474, the Castilian crown was disputed between the half-sister of the king, Isabella I of Castile, married to Prince Ferdinand II of Aragon, and the king’s daughter, Juana de Trastámara, popularly known as la Beltraneja – because her father was alleged to be Beltrán de la Cueva. In the subsequent civil war, Afonso V of Portugal married Juana and invaded Castile (May 1475), defending her rights.

Parallel to the dynastic struggle, there was a fierce naval war between the fleets of Portugal and Castile to access and control overseas territories − especially Guinea – whose gold and slaves were the heart of the Portuguese power. The main events of this war were the indecisivebattle of Toro (1 March 1476), transformed in a strategic victory by the Catholic Monarchs and the battle of Guinea (1478), which granted Portugal the hegemony in the Atlantic Ocean and disputed territories.

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