The Saint Chapelle was built by Louis IX, to house the relics of the Passion of Christ. It is adorned with a unique collection of fifteen glass panels and a large rose window forming a veritable form of light.
The building is a Palatine chapel, the upper part of which was reserved for the sovereign (a gallery linked the chapel to the royal suite) and in the lower part of which lived the staff of the Palace.
The walls of Chapelle are decorated with wall paintings, murals and sculptures.
--See: http://sainte-chapelle.monuments-nationaux.fr/en/