He was crowned king at 12, at his fathers death. His mother, Blanche of Castile, ruled during his minority. When he was 19, (and his bride 12) he was married to Marguerite of Provence. It was a loving marriage, though was not without challenge. They had 10 children.
Louis took the cross for a Crusade when he was 30. His army took Damietta on the Nile but not long after, weakened by dysentery and without support, they were surrounded and captured. Louis obtained the release of the army by giving up the city of Damietta in addition to paying a ransom. He stayed in Syria four years.
He deserves credit for extending justice in civil administration. He drew up regulations for his officials which became the first of a series of reform laws. He replaced trial by battle with a form of examination of witnesses and encouraged the beginning of using written records in court.
Louis was always respectful of the papacy, but defended royal interests against the popes and refused to acknowledge Innocent IVs sentence against Emperor Frederick II.
Louis was devoted to his people, founding hospitals, visiting the sick and, like his patron St. Francis, caring even for people with leprosy. (He is one of the patrons of the Secular Franciscan Order.) Louis united Francelords and townsfolk, peasants and priests and knightsby the force of his personality and holiness. For many years the nation was at peace.
Every day Louis had 13 special guests from among the poor to eat with him, and a large number of poor were served meals near his palace. During Advent and Lent, all who presented themselves were given a meal, and Louis often served them in person. He kept lists of needy people, whom he regularly relieved, in every province of his dominion.
Disturbed by new Muslim advances in Syria, he led another crusade in 1267, at the age of 41. His crusade was diverted to Tunis for his brothers sake. The army was decimated by disease within a month, and Louis himself died on foreign soil at the age of 44. He was canonized 27 years later.