Short answers, pulled from the story.
Louis IX of France, also known as Saint Louis, was King of France from 1226 until his death in 1270. He is the only French king canonised as a saint of the Catholic Church and the direct ancestor of all subsequent French kings.
Louis IX of France was born on the 25th of April 1214 at Poissy, near Paris, and died on the 25th of August 1270 at Tunis during an epidemic of dysentery. He was succeeded by his son Philip III.
Pope Boniface VIII proclaimed the canonisation of Louis IX in 1297, making him the only French king declared a saint. His reputation for piety, fairness, and charity made him a model of the ideal Christian monarch.
Louis IX abolished trials by ordeal and combat and introduced the presumption of innocence into criminal proceedings. He created a royal justice mechanism that let subjects appeal judgments directly to the monarch and promulgated the Great Reform Ordinance in December 1254 to govern royal officials.
Louis IX led the Seventh and Eighth Crusades. During the Seventh Crusade he was captured at the Battle of Fariskur on the 8th of February 1250 and ransomed, and during the Eighth Crusade he died of dysentery at Tunis in 1270.
Louis IX built the Sainte-Chapelle on the Île de la Cité as a shrine for the crown of thorns and a fragment of the True Cross. He acquired these relics between 1239 and 1241 and paid 135,000 livres to clear the debt of Emperor Baldwin II.