 It was 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 the "dead pond" - in French "morte mare" - and gave the monastery its name.The monks constructed what was then one of the largest Cistercian monastery in the world.