Louis IX was born at Poissy on April 25th, 1214. His father, Louis VIII, died when Louis IX was 11 years old; he was crowned King at Rheims on November 29th, 1226. His mother and regent, Blanche of Castile, inspired his early religious exercises of devotion and asceticism. At age 20, Louis married Margaret of Provence, who bore him 11 children, 9 of whom lived past infancy. Blanche remained a major influence on her son Louis IX until her death in 1252.

A man of unusual purity of life and manners, he was sincerely committed to his faith and to its moral demands. Living simply, dressing plainly, visiting hospitals, helping the poor, and acting with integrity and honesty, Louis IX believed that the crown was given him by God and that God would hold him accountable for his reign.

A deplorable aspect of medieval Christianity was its anti-Semitism, and despite his attempts to cultivate holiness, Louis IX was complicit in official action against Jewish believers. Louis ordered the expulsion of all Jews engaged in usury and the confiscation of their propertyto finance his crusade. At the urging of Pope Gregory IX, Louis also ordered the burning in Paris in 1243 of some 12,000 manuscript copies of the Talmud and other Jewish books and increased the power and authority of the Inquisition in France.

In the winter of 1244, Louis fell gravely ill. In an act customary of the piety and politics of his time and culture, he vowed that if he recovered he would lead a Crusade against the Muslims. Leavinghis mother Blanche in charge of the kingdom, Louis led the Seventh Crusade fortified with 36 ships and 15,000 soldiers, including two of his brothers. They began with an attack upon Damietta in Egypt, where Louis won an easy victory in June 1249 that quickly led to disaster as the troops progressed to Cairo. The Egyptian army was numerically superior, the French troops ravaged with famine and disease that forced the Crusaders back to Damietta. But on the way, the Egyptians defeated Louis at Fariskur on April 6th 1250, and he was taken captive. Released only after paying a very large ransom, Louis then went to Acre, where he engaged in a series of fruitless negotiations. When the money ran out, and learning of the death of his mother, Louis IX went home to France.

Back in France, Louis’ piety inspired his patronage of the arts and encouraged the spread of Gothic architecture. One of his most notable commissions is Sainte-Chapelle (“Holy Chapel”), located within the royal palace complex in the center of Paris, erected as a shrine for the Crown of Thorns and a fragment of the True Cross, precious relics of the Passion of Jesus that Louis had purchased in 1239–41 for a sum twice the total cost of the chapel itself.

The Eighth Crusade, launched by Louis IX in 1270 in response to Mamluk attacks against the Christian outposts in Syria, landed him in Tunis in July of 1270. Most of the soldiers dispatched ahead of him had developed diarrheal diseases from poor drinking water. Louis developed “flux of the stomach” and died August 25th, 1270. Louis’ brother, Charles of Anjou, continued the crusade to a negotiated settlement, and Louis’ son, Philip III, succeeded his father as king.