During a civil war in which this ruler commanded one side, his partisans repeatedly slaughtered Jews, whom his opponent had favored, and this ruler's greatest military triumphs were assisted by Bernard du Guesclin.
This ruler's introduction of the hereditary titles of duke and marquess as rewards for those loyal to him resulted in his acquiring the sobriquet, "He of the largesse." This ruler married his daughter Eleanor to Charles III of Navarre and after winning his highest position, he defended his throne against the claims of John of Gaunt. During a civil war in which this ruler commanded one side, his partisans repeatedly slaughtered Jews, whom his opponent had favored, and this ruler's greatest military triumphs were assisted by Bernard du Guesclin. Although this ruler lost the Battle of Najera to forces commanded by his half-brother and Edward the Black Prince, he would later gain revenge by capturing that half-brother at the Battle of Montiel. For 10 points, identify this illegitimate son of Alfonso XI, who after killing his half-brother Pedro the Cruel assumed the throne of Castile and founded a namesake house that ruled it until 1504.
This ruler's introduction of the hereditary titles of duke and marquess as rewards for those loyal to him resulted in his acquiring the sobriquet, "He of the largesse.
Henry II or Henry of Trastamara or Henry the Bastard