Peter the Cruel (Spanish: Pedro; 30 August 1334 – 23 March 1369), also known as the Just, was the king of Castile and León from 1350 to 1369. He was the son of Alfonso XI of Castile and Maria of Portugal, daughter of Afonso IV of Portugal. Peter was the last ruler of the main branch of the House of Ivrea.
Peter was born in the defensive tower of the Monasterio de Santa Maria la Real de Las Huelgas in Burgos, Spain.
According to chancellor and chronicler Pero López de Ayala, he had a pale complexion, blue eyes and very light blonde hair; he was tall (1.83 m) and muscular. He was accustomed to long, strenuous hours of work, lisped a little and "loved women greatly". He was well read and a patron of the arts, and in his formative years he enjoyed entertainment, music and poetry.
Peter began his reign when almost sixteen years old and subjected to the control of his mother and her favourites. He was to be married to Joan, daughter of Edward III of England; on her way to Castile, however, she travelled through cities infested with the Black Death, ignoring townspeople who had warned her not to enter their settlements. Joan soon contracted the disease and died.