St. Ferdinand III of Castile and Leon
Ferdinand was born in Salamanca in 1199 to king Alfonso IX of Leon and Berengaria (or Berenguela in Spanish), daughter of the king of Castile. His sister Blanche would be the mother of St. Louis IX of France. It was a very royal family.
At eighteen, Ferdinand became king of Castile when his mother ceded her right of succession in favour of him. He still had to fight his father to keep the kingdom, but they later reconciled and joined forces against the moors who still occupied the Iberian peninsula. King Alfonso died in 1230 and Ferdinand became king of Leon as well, uniting the two kingdoms despite protests from the populace and his two half-sisters. He also ruled the smaller kingdoms of Palencia, Valladolid, and Burgos, and eventually completed the reconquest of Spain from the Muslims, with the exception of Granada and Alicante.
The king spent 27 years battling, fending off the Muslim offensives and always winning more territory for the cross. His victories were legendary, literally: In the battle of Xerez, only ten Spaniards are said to have fallen, and the holy Saint Jacob himself is said to have appeared to lead the army, riding a white horse.
King Ferdinand won back important places of holiness such as the tomb of St. Jacob in Santiago de Compostela. After Ferdinand conquested Sevilla and Cordoba he turned the mosques there into cathedrals. In order to re-establish Christianity in the country, he established bishoprics in the most important towns and encouraged the funding of monasteries. He also founded many other places of healing, learning and devotion during his reign. The most outstanding are perhaps the Cathedral of Burgos and the University of Salamanca.
The king also compiled and reformed a code of laws which was used until the modern era, and was seen as a good, just and even holy king. Perhaps the greatest indicator of his holiness is his gentle treatment of the non-Christians, Jews and Muslims alike, after he had conquered their cities. Although he encouraged their conversion to his own religion, he never forced them or took away their property, the way other holy fighters have been wont to do. As with all medieval legendary person it is hard to say how much is true about him, but totally disagreeable he can not have been.
Following advice from his mother, Ferdinand's married Beatrice, the daughter of Philip of Swabia, who was Holy Roman Emperor. Together they had several children*. When the queen died in 1236 he married Joan of Ponthieu. Ferdinand died in 1252 and was succeeded by his son, Alfonso X. The king was buried dressed in the habit of his secular Franciscan order and his remains kept in the Cathedral of Seville. To this day they remain enterred there, hidden in a gilded silver box.
The king was highly committed to his religion, and his lifelong battle against the Saracens was a sort of personal crusade. He was a devout member of the Third Order of St. Francis, and is reported to have lived a strict life of prayer and penance, as fits a saintly man. Afer his death, many miracles were reported to take place at his tomb, and for all this pope Clement X canonised him in 1671. His feast day is on the 30th of May and he is a patron to the Spanish army, the poor, rulers and prisoners, engineers, governors, and fathers of large families.
* Sources differ on the number of children, but they all agree that there were any. The below list comes from http://www.worldroots.com.
Born to Beatrice:
Alphonso X of Castile
Fadrique, Infant of Castile
Enrique, Infant of Castile
Felipe of Castile, archbishop of Sevilla
Leonor of Castile
Sister Berenguela of Castile
Sancho Castille Toledo, archbishop of Sevilla
Manuel of Castille, senor Villena
Maria, Infant of Castile
Born to Joan:
Fernando of Castile, count Aumale
Luis of Castile, senor Marchenza
Eleanor of Castile, countess of Ponthieu, wife of Edward I and queen of England.
Simon of Castile
Juan of Castile
Leonor of Castile