Fernando de la Cerda (1255–1275)

Ferdinand de la Cerda was the heir apparent to the Crown of Castile as the eldest son of Alfonso X and Violant of Aragon. His nickname, de la Cerda, means "of the bristle" in Spanish. There are various accounts of the origin of this name, including that it was a reference to being born with a full head of hair or that he was born with a hairy mole, resembling a bristle or mane, on his chest or back according to different accounts.