Ferdinand was the son of Alphonso IX, king of León, and Berengaria, the oldest daughter of Alphonso III, king of Castile. His maternal grandmother was the daughter of Henry II of England, and her sister Blanche became the mother of Saint Louis of France.
The death of Berengaria's brother, Henry, left her heiress to the throne of Castile in 1217, but she ceded her rights to the 18-year- old Ferdinand. He was a stern, but forgiving, ruler who ignored personal slights, and an excellent administrator. The archbishop of Toledo, Rodrigo Ximenes, was chancellor of Castile and his principal adviser for many years. Ferdinand married Beatrice, daughter of King Philip of Swabia in 1219.
Upon the death of his father in 1230, Ferdinand became king of León. There was opposition to this, for there were supporters of the claim of his two half sisters, but his union of the two kingdoms made a recovery from the Moors possible. He campaigned against the Moors without respite for 27 years, and his success won the great devotion of his people. He recaptured the greater part of Andalusia, including Ubeda, Cordova (1236), Murcia, Jaen, Cadiz, and Seville (1249).
It was in the battle of Xeres, when only 10 or 12 Spanish lives were lost, that Saint James (Santiago) was said to have been seen leading the host on a white horse. Saint James's chronicle is a principal source for Ferdinand's achievements. Ferdinand's military efforts were not so much imperialistic in motivation as driven by a wish to save Christians from the dominance of infidels.
Although he was a warrior, it was said of him that "he feared the curse of one old woman more than a whole army of Moors." In thanksgiving for his victories, Ferdinand rebuilt the cathedral in Burgos and converted the great mosque of Seville into a church. He restored to the Cathedral of Santiago de Compostella the bells that had been removed by the Moors.
Once the Moors and Jews submitted, he pursued a course of tolerance, while encouraging the friars to convert them. He was the founder of the famed University of Salamanca in 1243. He married Joan of Ponthieu on the death of Beatrice. By his second wife he was the father of Eleanor, wife of King Edward I of England. It is interesting to note that upon his death he was buried in the habit of a Franciscan friar in the cathedral of Seville. At his death he was popularly acclaimed a saint but canonical recognition took another 400 years (Attwater, Benedictines, Delaney, White).
King Saint Ferdinand is depicted in art as a crowned knight with a greyhound. He is dressed royal regalia, cross on his breast, and the dog at his feet (Roeder). He is the patron saint of persons in authority (rulers, governors, magistrates, etc.)--a result of his wise appointments; the poor and prisoners (over whom such persons rule); engineers (a result of his technical military skills), and the Spanish army (White)