king of Aragon from 1285 to 1291, son of Peter III. A weak king, he was involved in an unsuccessful constitutional struggle with the Aragonese nobles. In 1287 he was compelled to grant the so-called “Privilegio de la Unión,” which handed over a number of important royal prerogatives to baronial control. At Alfonso's death the crown passed to his brother James II, who had been king of Sicily (as James I) since 1285.

king of Asturias from 866 to 910, son of Ordoño I.

Winning a contested succession, he moved his capital forward from Oviedo to the recently restored Roman city of León. Under him, Porto (Oporto) was occupied in 868, and Castile took shape around Burgos, drawing on his Basque allies. He claimed to be reviving the Visigothic monarchy, while making the church of St. James at Santiago de Compostela the shrine of the Christian kingdom. Alfonso's territorial advances were made possible by the convulsion of the Muslim emirate of Córdoba, in which Arab dominion was challenged by the Berber dissidents. For a time Córdoba itself was endangered, and the triumph of Alfonso was thought imminent. This did not occur, but by the end of the reign Alfonso III had occupied Coimbra, Zamora, and Burgos, settling refugees from the south and doubling the size of his kingdom. He was deposed by his sons in 910 and died in exile. He may have written himself or commissioned the Chronicle of Alfonso III, an important source for early Spanish history.