Henry II (January 13,1334 Sevilla - May 29,1379 Santo Domingo de la Calzada), better known as Henry of Trastámara (Enrique de Trastámara) before his coronation, was the illegitimate son of Alfonso XI of Castile and Eleanor of Guzmán, half brother to Peter of Castile. He took the throne after defeating and killing Peter in the Castilian Civil War (1366–1369).

As head of a band of mercenaries, and with the aid of Bertrand du Guesclin, he drove Pedro from his throne in 1366. He was, however, defeated the next year at the Battle of Nájera (Navarette), and Pedro was restored. Henry defeated Pedro at the Battle of Montiel and then murdered him in 1369. Henry then went to war against Portugal and England in the Hundred Years' War. For most of his reign he had to fight off the attempts of John of Gaunt, a son of Edward III of England, to claim the Castilian throne in right of his second wife, Pedro's daughter.

On 27 July, 1350, Henry married Juana Manuel, the daughter of Juan Manuel, Duke of Peñafiel, head of a younger branch of the royal house of Castile. They had three children: John (1358–1390), Eleanor (1361–1425), wife of Charles III of Navarre, and Joanna (1367–1374).

Henry was the first nobleman to use Anti-Semitism as a political tool in Spain. This led to an end to the convivencia, and a period of riots and pogroms, and can be seen as sowing the seeds of the persecution of the Jews by the Spanish Inquisition, beginning a hundred years later.

Henry II of Castile Henry II of Castile