Henry IV (Castilian: Enrique, Galician: Henrique) (5 January 1425 – 11 December 1474), King of the Crown of Castile, nicknamed the Impotent (ruled 1454–1474), was the last of the weak late medieval kings of Castile. During Henry's reign the nobles increased in power and the nation became less centralised.
More information on the Wikipedia page [1].