The first reference to the bishopric of Coutances dates from 511. A cathedral probably existed at this time. The building was razed to the ground by the Normans in 900 during the taking of the town, and was rebuilt from 1030 and completed by bishop Geoffroy de Montbray. It was dedicated in 1056. The Romanesque cathedral stood until the beginning of the 13th century, when it was replaced by the gothic building created under the episcopacies of Hugues de Morville and his successors.
The gothic building resumes the ground plan of the Romanesque cathedral; a nave with side aisles, a transept and three towers, two at the façade and the other above the transept crossing. The ground plan of the choir in the Romanesque church offers, on the other hand, too many uncertainties. The surviving Romanesque elements are in fact embedded in the walls of the current cathedral. These are the galleries of the nave and the Romanesque towers in the façade which are largely retained within the gothic walls. The towers presenting a square base are topped by an octagonal room, whose original fully arched openings have been walled. Vestiges of a gallery between two towers of the façade and at the transept crossing can still be discerned.

Bibliography

 - Mussat, André. “ La cathédrale Notre-Dame de Coutances ”, dans Congrès archéologique de France, CXXIVe session, 1966, Cotentin et Avranchin, Société Française d’Archéologie, Paris, 1966, p. 9 à 56.
- Dictionnaire des églises de France, Robert Laffont, Paris, 1968, T. IVb, p. 49 à 52.
- Fournée, Jean. “ Visite de la cathédrale Notre-Dame ”, dans Art de Basse-Normandie, Coutances, ville d’art, n° 95, 1er trimestre 1987, p. 68 à 107.