Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Peter I , called the Just, was the eighth King of Portugal and the Algarve from 1357 until his death. He was the third but only surviving son of Afonso IV of Portugal and his wife, princess Beatrice of Castile. Afonso IV married his daughter, Maria, to Alfonso XI of Castile, but quickly learned that she was being mistreated by her husband. Alfonso''s cousin, Juan Manuel, Duke of Peñafiel, had also been rebuffed by the king when his daughter Constanza was rejected in favor of the Portuguese princess. Feeling as though his daughter was being dishonored, Afonso was glad to enter into an alliance with Juan Manuel and married his son and heir, Peter, to Constance. When Constanza arrived in Portugal, Inês de Castro, the daughter of an aristocratic Castilian land-owner, accompanied her as her lady-in-waiting.