This jewel of 13th century Gothic architecture is today attached to the austere walls of the Palais de Justice. The Saint Chapel was built by Saint Louis in 1248 in order to house the Crown of Thorns of Christ and a piece of his cross, which is today in Notre Dame. In order to buy these relics from his cousin, the Emperor of Constantinople, and to build their reliquary (a trunk set in precious stones, later melted down during the Revolution), the King of France spent two and a half times the cost of the construction of the Saint Chapel. The Saint-Chapel was completed in 1348. It burned in 1630 and was rebuilt very slowly. During the Revolution its demolition was contemplated. It was then used as a storehouse for archives until 1837.