Sainte Chapelle (the Holy Chapel) was built by King Louis IX (1226-1270) to house what he believed was Christ's crown of thorns and fragments of the True Cross. He had bought these relics from the Emperor Baldwin of Constantinople. Of simple design, the chapel is actually two chapels. The first floor chapel, the plainer of the two, was built for servants and lowly members of the royal court. The vastly more elegant upper chapel was intended for the king and his nobles. The stained glass windows, shown in this photo, are the highlight of this upper chapel. The architecture of the chapel was intended to provide the maximum amount of window space and interior light, and the walls contain about twice as much surface area in windows as they do in solid masonry. Because of its beauty, this upper chapel is considered one of the most magnificent achievements of the Middle Ages.