Beatrice of Portugal, LG, was a natural daughter of John I of Portugal and Inês Pires, born before the marriage of her father with Philippa of Lancaster, daughter of John of Gaunt. She was a sister of Afonso, Duke of Braganza and half-sister of King Edward of Portugal, Infante Peter, Duke of Coimbra, Henry the Navigator, Isabella of Portugal, Duchess of Burgundy, John, Constable of Portugal, and Ferdinand the Saint Prince. Queen Philippa was in charge of the education of both of her husband's children out of wedlock.