Peter I of Castile

Peter I (1334–1369), called the Cruel or the Just, was king of Castile and León from 1350, the last ruler of the senior House of Ivrea. Born at Burgos to Alfonso XI and Maria of Portugal, he lost his intended bride Joan of England to plague in 1348. He came to the throne at almost sixteen, married Blanche of Bourbon in 1353 but left her within days for María de Padilla.

His long feud with half-brother Henry of Trastámara plunged Castile into civil war; he took refuge with the Black Prince, who restored him after Nájera in 1367. Henry returned in 1368 and defeated Peter at Montiel in 1369.

Du Guesclin led Peter into his tent, where Henry himself killed him and left the body unburied for three days. Chronicler Ayala, later a Trastámara servant, called him a tyrant, but the English remembered him and Chaucer lamented his fall.