High Quality Content by WIKIPEDIA articles! Isabella of Portugal (Portuguese pronunciation: ; 21 February 1397 – 17 December 1471) was a Portuguese infanta of the House of Aviz, the only surviving daughter of King John I of Portugal and his wife Philippa of Lancaster. Her most notable siblings were Henry the Navigator, Peter, Duke of Coimbra, and King Edward of Portugal. As third wife of Philip the Good, Duke of Burgundy, she was Duchess consort of Burgundy for most of her adult life; her son by Philip was Charles the Bold, the last Valois Duke of Burgundy. Isabella was the regent of the Burgundian Low Countries during the absence of her spouse in 1432 and in 1441–1443. She served as her husband`s representative in negotiations with England regarding trade relations in 1439 and those with the rebellious cities of Holland in 1444.