For 10 points, name this only French king to be canonized.
Early in this man's reign he faced revolts from Theobald IV of Champaign and Pierre Mauclerc, and his biographer was Jean de Joinville.  He defeated Hugh of Lusignan and the English at the Battle of Taillebourg, and with James I of Aragon he signed the Treaty of Corbeil.  With a Treaty of Paris he ensured Languedoc would become a royal possession, ending the Albigensian Crusade,  and he constructed the Sainte-Chapelle.  This son of Blanche of Castille captured Damietta before failing to take Cairo, ending the Seventh Crusade.  For 10 points, name this only French king to be canonized.
Early in this man's reign he faced revolts from Theobald IV of Champaign and Pierre Mauclerc, and his biographer was Jean de Joinville.  
Louis IX [or Louis II of Artois; prompt on Saint Louis]