– 9 August 1460) was the eldest son of Afonso, 1st Duke of Braganza, natural son of King John I of Portugal, and of his wife, Beatriz Pereira Alvim, the only daughter of Nuno Álvares Pereira and Leonor de Alvim.
[1][2] Through a formal document dated 4 April 1422, his maternal grandfather, the Constable Nuno Álvares Pereira, granted to him the County of Ourém.
In a document issued on 11 October 1451, King Afonso V of Portugal granted him the title of Marquis of Valença.
During October 1451, he escorted Infanta Eleanor of Portugal (King Edward's daughter) on her journey from Lisbon to Livorno, where she met her betrothed, Frederick III, Holy Roman Emperor.
In 1458, Alphonse took part in the Portuguese expedition to north Africa which led to the capture of the Moroccan city of Alcácer Ceguer (Al Qsar as-Seghir).