Founded at the request of Archangel Michael by the Bishop of Avranches, Aubert, the first sanctuary was sanctified on 16 October 709. It became the heart of a great Benedictine abbey, highly resected in the Middle Ages for its treasury and rich library.
The abbey church is characterized by two architectural styles. On the one hand, the nave and the transept, dating from Roman times, on the other hand the choir and chapels high during the Gothic period. The nave, built in part on the Carolingian abbey church dates from the 11th century. It will be reduced by three bays in the 18th century.
The arms of the abbey of Mont Saint-Michel are: Sable ten silver shells 4, 3, 2 and 1; sewn to the head Azure, three gold fleurs-de-lis.