He erected the Saint-Chapelle to hold the Crown of Thorns and a fragment of the True Crosss.
During this man's absence the clergy were attacked by a mysterious leader known as the "Hungarian Master" who led a mob known as the Pastoureaux. An illuminated manuscript which was at one point given to Abbas I as a gift known as the Morgan Bible is sometimes attributed to this king. In the Mise of Amiens he flatly denied the claims of the barons and their bid to bind Henry III in the Provisions of Oxford. He erected the Saint-Chapelle to hold the Crown of Thorns and a fragment of the True Crosss. After a successful siege of Damietta he captured at the Battle of Fariskur by the Mamluks under Baibars, for 10 points, name this only canonized King of France. 
During this man's absence the clergy were attacked by a mysterious leader known as the "Hungarian Master" who led a mob known as the Pastoureaux.
Louis IX [prompt on St. Louis]