Don Ferdinand de la Cerda (1253–1275) was the Crown Prince (infante) of Castile, eldest son of King Alfonso X of Castile and Violant of Aragon. His nickname, de la Cerda, means "of the bristle" in Spanish, a reference to being born with a strand of thick hair running down his chest.
Alfonso de la Cerda , who married Matilde of Narbonne, daughter of Viscount Aimery VI of Narbonne.Medieval Iberia: An Encyclopedia, Ed. E. Michael Gerli and Samuel G. Armistead, (Routledge, 2003), 50. They had four sons and three daughters.