Trastámara

The House of Trastámara was a Castilian dynasty, an illegitimate cadet line of the House of Burgundy. It took its name from the County of Trastámara, the land beyond the Tambre river, held by its founder Henry before he took the crown.

During the Castilian Civil War of 1351–1369, Henry, a bastard son of Alfonso XI, fought his half-brother Peter I; after defeat at Nájera in 1367, he returned with French and Aragonese support and killed Peter in 1369, reigning as Henry II. In 1412 the Compromise of Caspe placed the Trastámara prince Ferdinand of Antequera on the throne of Aragon.

Isabella I of Castile and Ferdinand II of Aragon, second cousins of the same house, married in 1469, joining the crowns in a dynastic union. Their reign saw the Inquisition, Granada's fall in 1492 and the decree expelling Jews. The crowns passed to their grandson Charles V, the first Habsburg king of Spain.