Henry IV of Castile, King of the Crown of Castile (born 1425)

Henry IV of Castile, nicknamed the Impotent, was King of Castile and León and the last of the weak late-medieval kings of Castile and León. During Henry's reign, the nobles became more powerful and the nation became less centralised.

The Crown of Castile was a medieval polity in the Iberian Peninsula that formed in 1230 as a result of the third and definitive union of the crowns and, some decades later, the parliaments of the kingdoms of Castile and León upon the accession of the then Castilian king, Ferdinand III, to the vacant Leonese throne. It continued to exist as a separate entity after the personal union in 1469 of the crowns of Castile and Aragon with the marriage of the Catholic Monarchs up to the promulgation of the Nueva Planta decrees by Philip V in 1716.