Alfonso III, 1210–79, king of Portugal (1248–79), son of Alfonso II, brother and successor of Sancho II. By his marriage with Matilda, countess of Boulogne, he became count of Boulogne and thus was known as Alfonso o Bolonhez [Alfonso of Boulogne]. He seized power after the deposition (1245) of his brother by the pope, becoming king on Sancho's death. Alfonso completed the reconquest of Portugal from the Moors by taking (1249) the rest of the Algarve. This involved him in a long quarrel with Alfonso X of Castile, who had been receiving revenues from Algarve, but the two kings reached an agreement by which Alfonso III married the illegitimate daughter of Alfonso X, and Alfonso X was to relinquish all rights to the Algarve when the heir born of this union (the later King Diniz) should reach the age of seven. Alfonso's second marriage brought the Portuguese king into disfavor with the church because Matilda was still living, but her death ended the conflict. Despite promises he had made at the time of Sancho's deposition, Alfonso seized lands and revenues from the church. This caused another break with the church, which healed shortly before his death. Alfonso called the Cortes of Leiria (1254), the first Portuguese Cortes to include commoners. He also instituted administrative and financial reforms, encouraged commerce and the development of the towns, and commuted many feudal dues into money payments. French and Provençal culture was imported to the court, and the period was one of great intellectual activity. Alfonso was succeeded by Diniz.
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