Sens Cathedral was influential in its strongly vertical appearance and in its three-part elevation, typical of subsequent Gothic buildings, with a clerestory at the top supported by a triforium, all carried on high arcades of pointed arches. In the following decades flying buttresses began to be used, allowing the construction of lighter, higher walls. French Gothic churches were heavily influenced both by the ambulatory and side-chapels around the choir at Saint-Denis, and by the paired towers and triple doors on the western façade.