The hall called Knights’ hall was begun in 1215 by Robert des Isles who died in 1218. Thomas des Chambres who succeeded him finished it about 1220. It was called Knights’ hall only after the institution of the Order of Saint-Michel, established by Louis XI in 1469; it was used before as the Hall of the general assemblies or as that of the Chapter of the Abbey.
Besides, the general arrangements of the Knights’ hall show it was destined for numerous meetings; what proves it, independently of its vast proportions, are the three latrines constructed especially and only for that hall; two stands on the north and outside, between the buttresses joined by arches. Each of them is preceded by a small recess communicating with the hall, lighted by two rows of trefoiled series of arches. A third latrine which is really the one for the old abbatial buildings of the XIth century and which was used by the builders of the XIIIth century is in the southwest angle. The visitor arrives there by a small chamfer door, and a passage built in the thickness of the west wall.
The Knights’ hall is formed of four naves of unequal width; the first two rows of columns, towards the north, rest on the piers of the Cellar; the third row has its foundations on the rock. The vaults composed of transverse and pointed arches, adorned at their junction with a sculptured keystone, are supported by round columns with octagonal bases very finely cut; the capitals, richly and strongly sculptured are surmounted, like those of the Refectory by circular abacuses with high side faces deeply indented which have all the peculiar characters of the norman buildings of the XIIth century.
Two large chimneys stand on the north front wall ; their large pyramidal mantels rise to the vault to which their summits are very cleverly joined. The flues of these chimneys go outside with a series of corbels ingeniously combined with the buttresses , the uppermost part of which they overtop, and their shafts crown the lateral wall of the Cloister.
The hall is lighted on the north by windows of different forms, and on the west by a large opening, now glazed; which used to communicate with the constructions (now in ruins), raised or only begun by Richard Tustin about 1260. On the south aisle, joining the romanesque substructures of the north transept is a lateral passage, standing at two meters above the level of the Hall, which makes a communication between the Refectory and the other parts of the Abbey, especially the Church, the Cloister, the Ambulatory and the west substructures.
In the interior north-west angle, close to the staircase leading down to the Cellar, is the entrance to the Charter house, built on the exterior north-west angle of the Merveille. The Charter house is composed of two small rooms placed one above the other, the first of which is alone vaulted ; a winding staircase connects them inside ; the end of the second floor is parallel with the west gallery of the Cloister, which is above the Knights’ hall.
At the southeast angle of the Hall, a door opens into the large porch which is in front of the Refectory. This porch, in the middle of which the Benedictine monks of the congregation of Saint-Maur placed, in 1650, a staircase which is short to be pulled down, opens, or rather, after the demolition of the staircase of the XVIIth century will open its arches to the north on a small court, in front of the north door of the lower Church. After descending some steps on the north we reach the Refectory.