Henry I of Castile

Henry I (Spanish: Enrique; 14 April 1204 – 6 June 1217) was the king of Castile from 1214 until 1217. Throughout his short reign, the boy king was a puppet monarch torn between his sister and heir, Queen Berengaria, and guardian, Count Álvaro Núñez de Lara.

Henry was the only surviving son of Alfonso VIII of Castile and Eleanor of England. He succeeded to the throne upon Alfonso's death on 5 October 1214. Because Henry was only ten at the time and his mother died within weeks, his older sister Berengaria took up rule as regent in his name. Discontented nobility forced her to give up rule and custody of Henry to Álvaro in early 1215. In an attempt to solidify his rule by procuring alliances with other Iberian rulers, Álvaro arranged for Henry to marry Mafalda of Portugal, but Berengaria intervened to have the marriage annulled; Álvaro then attempted to betroth Henry to Sancha of León in 1216, but the Leónese rejected the offer.