With its square six-part vaults built on alternating strong and weak columns, it served as a model for subsequent reflections.
While the double ambulatory of the Rayonnant choir chapels from Saint Denis Abbey Church, built near Paris between 1140 and 1144, is considered the first example of Gothic architecture, the first novelties appeared at Sens Cathedral, which was begun around 1135.  With its square six-part vaults built on alternating strong and weak columns, it served as a model for subsequent reflections. Other innovations appeared at Noyon Cathedral, which features an interior elevation of four levels (large arcades, galleries, triforium, and upper windows), and at Laon Cathedral, which was built with homogenous pillars, an arrangement that was subsequently synthesized at Notre Dame. These buildings, all of which were begun in the third quarter of the twelfth century, are illustrations of what is called the “primitive Gothic,” which even appeared outside of France (Canterbury Cathedral, beginning in 1175).