Isabella of Portugal (21 February 1397 – 17 December 1471) was
Duchess of Burgundy as the third wife of Duke
Philip the Good. Born a
Portuguese infanta of the
House of Aviz, Isabella was the only surviving daughter of King
John I of Portugal and his wife
Philippa of Lancaster. 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.