Louis IX or Saint Louis, 1214-70, king of France (1226-70), son and successor of Louis VIII. His mother, Blanche of Castile, was regent during his minority (1226-34), and her regency probably lasted even after Louis reached his majority; she was his chief adviser until her death. During the early years of the reign, the queen mother suppressed several revolts of the great nobles, led by Pierre Mauclerc (Peter I), duke of Brittany, and supported by Duke Raymond VII of Toulouse and King Henry III of England. In 1240-43, Louis subdued new revolts in S France, securing the submission of Poitou and of Raymond VII, and repulsing a weak invasion (1242) by Henry III. Louis took the cross in 1244, but did not leave on the crusade to Egypt (the Seventh Crusade; see Crusades) until 1248. Defeated and captured (1250) at al-Mansurah, he was ransomed but remained in the Holy Land until 1254, helping to strengthen the fortifications of the Christian colonies. After his return he attempted to bring about a peaceful settlement of territorial claims with Henry III. Agreement was reached in the Treaty of Paris, ratified in 1259. By its terms Louis ceded Limoges, Cahors, and Périgueux to Henry in exchange for Henry's renunciation of Normandy, Anjou, Maine, Touraine, and Poitou and his recognition of the king of France as suzerain for the reduced duchy of Aquitaine. Louis made a favorable treaty with King James I of Aragón by yielding the French claim to Roussillon and Barcelona in return for James's abandonment of his claim to Provence and Languedoc. A respected arbitrator, Louis settled succession disputes in Flanders and Hainaut and in Navarre; he attempted unsuccessfully to settle the bitter controversy between Henry III and the English barons by judging in favor of the king. In 1270, Louis undertook the Eighth Crusade, but he died soon after landing in Tunis. He was succeeded by his son, Philip III. Under Louis IX, France enjoyed unprecedented prosperity and peace. Louis continued the reforms of his grandfather, Philip II. He curbed private feudal warfare, simplified administration, improved the distribution of taxes, encouraged the use of Roman law, and extended the appellate jurisdiction of the crown to all cases. Louis was pious and ascetic, yet a good administrator and diplomat. He was canonized in 1297. Feast: Aug. 25.

or St. Louis

(born April 25, 1214, Poissy, France—died Aug. 25, 1279, near Tunis, Tun.; canonized Aug. 11, 1297; feast day August 25) King of France (1226–70). He inherited the throne at age 12. His mother served as regent until 1234, helping to subdue rebellious barons and Albigensian heretics (see Cathari). Louis led a Crusade (1248–50) in hopes of regaining Jerusalem and Damascus, but his troops were badly defeated by the Egyptians. On his return he reorganized the royal administrative system and standardized coinage. He built the extraordinary Sainte-Chapelle to house a religious relic believed to be Jesus' crown of thorns. Louis made peace with the English in the Treaty of Paris (1259), allowing Henry III to keep Aquitaine and neighboring lands but obliging him to declare himself Louis's vassal. He died of plague during a Crusade. The most popular of the Capetian kings, his reputation for justness and piety led the French to venerate him as a saint even before his canonization in 1297.

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