12th and 13th centuries, Chevet of Saint-Etienne Cathedral.
In 1195 the archbishop Henri de Sully decided to rebuild the cathedral in the new Gothic style, starting with the apse in the east.
The chevet rises over the lower church (mistakenly called the "crypt"), built over the Gallo-Roman wall in order to save space. This view of the cathedral, is vista opened in the 19th century by the creation of Strasbourg Boulevard, discloses the basic structure of Saint-Etienne : a three-story pyramid, corresponding to the nave and double ambulatory within. The flying buttresses have two batteries of arches, each containing two registers.
Five radiating chapels add extra space for stained-glass.