View of the nave vault, looking east from beneath the organ. The nave soars to great height and is filled with light, thanks in large part to its rather ingenious system of vaulting. In a design that seems to have been invented in Tournus, the nave has a succession of transverse barrel vaults. This transfers the weight of the vault to the pillars, allowing for large windows in the clerestory. This design did not catch on: it was only implemented in one other church (Mont-Saint-Vincent, not far away).