Alfonso VI, 1643–83, king of Portugal (1656–83), son and successor of John IV. Slightly paralyzed and mentally defective, he led a dissolute youth until he came under the influence of the count of Castelho Melhor in 1662. The count of Castelho Melhor then took over the government and ruled ably. Under Castelho Melhor's direction the army won the series of victories over Spain (1663–65) that finally secured Spanish recognition of Portuguese independence (1668). After Alfonso's marriage (1666) to Marie Françoise of Savoy, daughter of the duc de Nemours, the young queen took a hand in government. She and the king's younger brother (later Peter II) fell in love, and in 1667 they forced Castelho Melhor from power and made Alfonso sign over the government to Peter, who became prince regent. A quick annulment of her marriage to Alfonso enabled Marie Françoise to wed the new regent. Alfonso was confined in the Azores until 1674 and at Sintra thereafter.
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