Begun in the 12th century on even older foundations, the building combines the work of three design periods with striking effect, the heavy and severe character of the Romanesque nave contrasting remarkably with the transitional work of the transept and the fully developed Gothic of the choir.

Pilasters between the round-arched windows in the clerestory help support the 18th-century vaulting that replaced the original ceiling, which was of wood, and flat.

The transept arms, built in about the mid-12th century, have apsidal ends, a feature borrowed in all probability from certain Rhenish churches, and which would appear to have made its influence felt in the north-east of France, as at Noyon and Soissons.

The rest of the cathedral was supposed to be rebuilt in the same style as the choir, but this was never attempted, the only later additions being the western porch, and a large Gothic chapel which was built alongside one of the side aisles, whose original walls and windows disappeared in the process.

Assessment of the damage revealed underlying structural problems and the cathedral has been undergoing extensive repairs and archaeological investigation ever since.