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.