Dome

North façade, a pinnacle; The plan as conceived by the first architect was highly original. It included a five-aisled nave of five double bays, a wide non-projecting transept and a choir of two double bays flanked by double aisles, which continued into a double ambulatory. The chapels were contained within the ambulatory wall. The north transept wall was built ca. 1250 by Jean de Chelles with a sculptured portal and a glazed triforium surmounted by an enormous rose window. He designed an identical arrangement for the south arm, but the project was continued by Pierre de Montreuil from 1258. In the 14th century Jean Ravy, continuing the work of Pierre de Chelles, enlarged the gallery windows of the chevet, decorating them with gables, and put up fantastic flying buttresses with a single span of 15 m. Source: Grove Art Online; http://www.groveart.com/ (accessed 2/9/2008)