La Cerda, the name of an ancient Spanish family, which traced its origin to Fernando, the eldest son of Alfonso X. of Castile, called La Cerda, or the horse's mane, from a large tuft of hair which grew upon his shoulders. In 1269, at the age of 15, this prince married Blanche, daughter of St. Louis of France. Fernando died in 1275, leaving two sons, Alfonso and Fernando, heirs to the crown. But Sancho, second son of Alfonso X., claimed the succession, and caused himself to be proclaimed in his father's lifetime. Yolande, the wife of Alfonso, fled from Castile with her grandchildren, to find a protector for them in her brother Don Pedro, king of Aragon, or in their uncle Philip the Bold of France. These kings resolved that the young princes should remain prisoners in Aragon, and Yolande returned to Castile alone. Blanche, the mother of the princes, wandered through France and Aragon, vainly exclaiming against the injustice of this decision. Alfonso X. died in 1284, and in his will made Alfonso and Fernando de la Cerda his heirs, and even in their default excluded from the throne that son by whom the latter years of his life had been embittered.

So sweeping a disinheritance was of little force, and caused slight hesitation between the unfortunate children and Sancho, already in possession of the throne, whose victories over the Moors had just given him the surnames of the Strong and the Valiant. At length, when it became the interest of the king of Aragon to embarrass the king of Castile, he set the princes of La Cerda at liberty. They were proclaimed at Badajoz and Talavera; but being unable to maintain themselves in Castile, they passed into France in the reign of Philip the Fair. They received from him but slight assistance, and their military operations were unfortunate. Sancho had died and had been succeeded by his own son. The kings of Portugal and Aragon, being invited to act as mediators between the ruling and the proscribed branches of the family, gave a decisive sentence in favor of the former, stipulating only that three cities should be ceded to Alfonso to aid him in maintaining the dignity of his birth. Alfonso, deserted by all his defenders, accepted the terms, and received the surname of the Disinherited. He died in 1325, leaving two sons.

One of these, Carlos de la Cerda, known also as Charles of Spain, was appointed by King John in 1350 constable of France. But the French court was soon disturbed by a rivalry between Charles of Spain and Charles the Bad, king of Navarre; and in 1354, while on a visit to his young wife in the castle of L'Aigle in Normandy, the former was poniarded by assassins in the pay of the king of Navarre. In 1425 the house of La Cerda became extinct, but it is still represented in the female line by the dukes of Medina-Cceli.