While the upper vaulting of Chartres was being finished and the choir of Rheims was building, there was laid the first stone of Notre Dame of Amiens in 1220. Amiens is the Gothic cathedral par excellence, recognized from the first as a masterpiece--the Parthenon of Gothic--and immediately taken as a model. The cathedrals of Tours and of Troyes, already begun, were now continued like the big church of Picardy. The Sainte-Chapelle in Paris was modeled on the Lady chapel of Amiens. The cathedrals of Clermont, Narbonne, Rodez, and Limoges are "daughters of Amiens." Its influence extended to the church of St. Sauveur at Bruges, to the cathedral of Prague, and to the choir of Cologne, the latter being almost a replica.[124] Amiens carried the Gothic principle of equilibrium farther than Rheims. The aisles were made higher, the bays wider, the points of ground support fewer, and the piers less heavy. No energy was wasted. Each part was made just strong enough. To go beyond this culminating point of constructive boldness was inevitably to decline. No one has better summed up the amplitude of this inspired church than M. Georges Durand, its latest historian, whose monograph is a model: "A vast space inundated with air and light has here been covered by stone vaults, as light and solid as possible; those vaults have been raised to a height never before attained; no longer any walls; the solidity of the edifice is assured by a play of pushes and resistances; flying buttresses exactly meeting the necessary spot to counterbut the great vault; the system of equilibrium perfectly known, and applied with a rigor and audacity unbelievable; the least possible sharpness given to transverse arches; the collaterals raised to a great height--all contribute to give this interior its expression of immensity." Amiens is a "triumphal chant." The "vast space inclosed" produces an impression that is confounding. When first you step inside the western doors of Amiens, you pause in awe. The emotion felt has the efficacy of a prayer.