Originally built in 1134, on land presented as a gift to the Cistercians by Henry I of England. The stagnant water of the drainage lake, dug out by the monks to dry up the marshy-land around the quick running Fouillebroc stream, was called "dead mere", "dead pond" - in modern French "morte mare" - and gave the monastery its name. The monks constructed what was then one of the largest Cistercian monastery in the world. Over the centuries, the abbey fell into decline and disrepair. It was rebuilt in the 17th Century, but the decline was irreversible, and by 1790, when it was dissolved during the French Revolution, only five monks remained.



Of the 12th century buildings, the cloisters remain almost intact, but the rest is only a shell. The 17th century buildings are well preserved and open to visitors. The abbey site also has a well-maintained 17th century dovecote, which was also used as a gaol house in the 18th and 19th centuries.



There are a number of legends and ghost stories relating to the abbey. Matilda of England was forced by her father Henry I of England to stay in a room in the abbey for 5 years. After her death in Rouen, she is said to have come back to haunt the place. Her ghost is known as The White Lady. Visitors to the abbey have reported hearing strange noises and feeling a strange presence. Four monks were murdered during the French Revolution, and their ghosts are also said to haunt the abbey. If you meet a cat in the ruins, it is alleged to be a Goblin cat (in Norman, "eul cat goublin"), guarding the treasure of the abbey. There are a number of other legends, giving the abbey the nickname of as most haunted abbey in France.