Begun in the 12C, rebuilt in the 13C following a fire, embellished in the 15C and again in the 16C, the splendid cathedral of Rouen is one of the most attractive French Gothic edifices. Its nave with eleven bays covered with a superb six-part vault and the lantern tower endow the edifice with a stunning sense of proportion. The chancel is striking for its balanced proportions and fourteen slender pillars. In the transept, the Staircase of the Libraries is a genuine masterpiece.