Keystone (bouquets of trefoil leaves)

This keystone can be stylistically compared to the nave of the abbey church of Saint-Denis, erected in several stages during the 13th century. It is circular and was taken off the ribs that attached it to the vault. 

Its decor is made up of trefoil leaves that are no longer fully stylised, but which are not yet as natural as those in the contemporary building sites of Pierre de Montreuil at Saint-Germain-des-Prés Abbey.

Taking on a triangular shape, the central leaves are arranged in a geometric pattern within a circle formed by a peripheral corolla of clusters of secondary leaves. The twelve leave blades spread out in this way form a delicate half-sphere-shaped veil of stone, interrupted by the deeply buried openwork deeply undercut between the stems. 

This virtuoso work, which skilfully plays on effects of shadow and light as contrasts between the empty spaces and solid parts, was originally complemented by bright polychromy, of which only traces remain. The lush and expertly arranged vegetation that flourishes on this key and on the capitals of the triforium was bathed in the intense light that flooded through the vast Rayonnant art windows.