Henry IV, 1425–74, Spanish king of Castile and León (1454–74), son and successor of John II. His weakness opened the way to civil strife and anarchy. The Castilian nobles refused to recognize Henry's alleged daughter Juana la Beltraneja as his heiress and forced the king to designate first his half-brother Alfonso (d. 1468) and then his half-sister Isabella (later Isabella I) as his successor. After Isabella's marriage (1469) to Ferdinand of Aragón, however, Henry again recognized Juana. On Henry's death civil war broke out among the contenders for the succession.
See study by T. Miller (1972).
