- (1373-1412) Daughter of King Fernando of Portugal and Leonor Teles.
- At a very tender age, she was betrothed to Fadrique, Duke of Benavente, son of Enrique II of Castile (1376). The ceremony was witnessed by her uncles, Prince João and João Master of Avis, and proctored by Fernán Pérez de Andrade, proctor for the groom, Fadrique, and his father, the king of Castile. [Fernando, ch. 96]
- Second wife of Juan I of Castile (1383).
- Though she was the Portuguese legitimate heir, she never reigned because when King Fernando died (1383), Juan I of Castile, her husband, invaded Portugal in breach of the treaty signed on the occasion of her marriage, and the Portuguese resented having a Castilian king.
- Beatriz made use of medieval queens' traditional role of mediator entreating her husband, Juan of Castile, to be merciful and accept the surrender of the castle of Almada, Portugal, after a punishingly long siege. Juan, however, having found out from a prisoner how famished and depleted of provisions the inhabitants of the castle were, had rather wait longer even till everyone had died of hunger. Three days later, however, yielding to the Queen's plea, he accepted the keys to the castle and guaranteed the safety of its inhabitants and their belongings. [João1, ch. 137: 33-56]
D. Beatriz (filha de D. Fernando)
Queen Beatriz of Castile