Construction from 1220 to 1225 Master Robert de Luzarches began work on the foundations and lower wall. He may have been assisted by Thomas de Cormont. Years 1225 to 1230 Master Robert de Luzarches and Thomas de Cormont constructed the south nave aisle rapidly to provide space for liturgical celebrations. Years 1230 to 1235 Master Robert de Luzarches and Thomas de Cormont built the north nave aisle soon afterwards. Years 1240s to c1250 Master Thomas de Cormont constructed the upper nave and belfries of western towers. Year c1250 Master Thomas de Cormont died having completed the upper nave, begun the upper transept and laid out the lower choir. Years 1250s to 1260s Master Renaud de Cormont completed the upper transept.. .. and upper choir. The axial window of the choir clerestory was installed in 1269. Years 1280s to c1310 Main roof installed from east to west. Years 1360s to c1400 Construction of west towers. Old steeple destroyed by lightning in 1528. onstruction of the grand clocher doré completed c1533.