Louis IX, also called St Louis 1214-70
King of France

In 1226 he succeeded his father, Louis VIII; his mother, the pious Blanche of Castile, was his regent until 1234. Making Blanche regent again, he joined the Seventh Crusade (1248-54), but was defeated and captured, and ransomed for one million marks in 1250. He remained in Palestine, fortifying Christian strongholds, until his mother's death (1252). His long and peaceful reign strengthened the Capetian dynasty. He founded the Abbey of Royamount (1228), built the Sainte-Chapelle in Paris to hold the crown of thorns relic he acquired from Constantinople (Istanbul), determined by the Pragmatic Sanction the relations between the French Church and the Pope, countenanced the Sorbonne, set up in the provinces royal courts of justice or parliaments, and authorized a new code of laws. By the Treaty of Paris (1259) he made peace with England, recognizing Henry III as Duke of Aquitaine in exchange for French suzerainty elsewhere. In 1270 he embarked on a new crusade, but died of plague in Tunis. He was canonized by Pope Boniface VIII in 1297, and his feast day is 25 August.

Bibliography: William C Jordan, Louis IX (1979)