During the first part of the XVth century, Pierre le Roy built the Chatelet and the Curtain joining that work to the Merveille by means of the Gorbins’ tower :
“And from this tower to Belle-Chaise he ordered the wall which is seen there to be built. Near it was constructed the dungeon above the flight of steps at the entrance of the Guard-house.” (Dom Jean Huynes.)
He also constructed the Barbican, comprising the sally port of the Chatelet and the Door of the Abbey, as well as the large flight of steps on the north side and the staircase on the south.
The Chatelet (dungeon) was built in front of the north external front of Belle-Chaise, on which it leans without joining, leaving between this front and the south one an empty space, a large machicolation protecting the northen door, which has become the second inward door since the Chatelet has been constructed. It comprises a square building, which contains in the angles of the north front, two little towers with corbels, resting on buttresses and which look, like two immense bombards, standing on their breeches. Between the pedestals of those small towers is the door, where are the stairs — leading to the Guards’ Hall — which were protected by a portcullis worked from the interior to the first floor of the Curtain joining the two small towers.
The Chatelet includes as well as the raking-vault of the staircase, a nook left between that vault and the floor of the first room — now the guardians’ office, in the court of the Merveille — and in which was the loop-hole pierced above the Door; three floors lighted on the east and on the north and each of them was provided with a chimney the top of which rises above the roof.
The wall or Curtain joining the Merveille and the Chatelet built at the same time as this last building, gives internally on the court of the Merveille the toothings of a planned building, the door and the postern of which alone were finished, on the north front of Belle-Chaise and looking on the court of the Merveille of which they were to make the entrance. This construction was not finished as is proved by the slate of the wall arches of the lower part, which was probably vaulted.
The Chatelet and the Curtain are admirably built of granite; their stones forming grey and pink lines alternately to the height of the first floor (of the Chatelet only) as well as the profiles of the mouldings, are cut with the greatest perfection. By these means they are very well conserved, and, except the necessary rebuilding of the timber-roof, ruined in part, it is possible to put them in their primitive state without very important works.
The perspective view taken from the north door of the Barbican, figures the entrance to the Abbey in its actual condition, except the battlement of the Barbican which is supposed to be rebuilt: the Chatelet, the door of which opens between the buttresses supporting the small towers, where begins the flight of steps which ascends to the Guards’ Hall (Belle-Chaise) and, on the right of the figure, the Curtain joining the Chatelet to the Merveille; on the left, the south door of the Barbican.
BARBICAN OF THE CHATELET
LARGE FLIGHT OF STEPS ON THE NORTH AND STAIRCASE ON THE SOUTH
The Barbican surrounding the Chatelet on the east and on the north, forms a first line of defence the battlement of which is reached by a small staircase. An embattled watch-tower stands in the south-east angle near the south door — M — it is provided with a chimney with machicolations, and was used as a shelter for the military guardians of the two doors of the Barbican.
A Curtaia joining the Chatelet to the Merveille.
B Court of the Merveille.
C Guards’ Hall.
First step of the entrance to the Abbey.
E Large flight of steps. — Stair head communicating with the postern I.
F Fligth of steps continuing the slopes of the streets of the town.
G First fortified door of the first flight of steps.
H Second fortified door ditto.
I Postern opening on the Claudine tower J and on the Ramparts by the staircase on the left.
J Claudine tower. — Guard-house.
K Third fortified door of the large flight of steps. — North door of the Barbican.
L South staircase.
M South door of the Barbican. — On the right of the staircase, guardhouse on the level of the Barbican.
N Postern communicating with the circular roads on tlie south.
“In front of the door of the Abbey were sometimes established advanced military works, in order to render more difficult the approach of the assailants, as would have been done before a fortress: those were barbicans which, in the case of an attack gave time to prepare for the defence and to close the gates. A remarkable specimen of those first military works was to be seen at Saint-Jean-des-Vignes, at Soissons (barbican of a rectangular form having a great analogy with that of Mont Saint-Michel). These advanced constructions — barbicans, — which were established in the middle ages in front of a place, were equivalent to the works named tête de pont demi-lune (or ravelin) in the modem fortifications. » (Albert Lenoir, monastic architecture .)
LARGE FLIGHT OF STEPS AND STAIRCASE ON THE SOUTH
Two staircases lead to the Barbican: the north one is the large flight of steps, very wide, the steps of which are very low, and form the suite of the slopes of the street of the town, ending at the exterior defences of the Castle.
The large flight of steps is established in a parallel with the west rampart, but without any communication with it; formerly a fortified door stood on the lower part of the stairs; a second door stopped the passage halfway, on a landing place where a small postern on the level of the landing-place communicating with a guard-house built in the lower part of the Claudine Tower, allowed the military to go on the flight of steps at the first signal. Lastly was a third door opening into the Barbican.
The south staircase is not so important; it established the necessary communications between the Barbican and the outside part by a postern built on the foot of the staircase and the exterior circular roads leading to the Barbican.
These traces give incontestable proofs of the primitive dispositions which we have reestablished in the following drawing.
The large flight of steps is reestablished as well as the first door; this one, the intermediary door and the Barbican door, are provided with folding sides parallel with the flight of steps.
This large flight of steps so powerfully fortified by nature and by military art, was entirely independent of the Ramparts with which it could however communicate, for the needs of the defenders, but only by a narrow postern opening on the large flight of steps, the passage of which was easily intercepted. The ramparts on the west and on the north, rose above the large flight of steps, and made it easy to be defended. A great part of those works still exist and the study of their traces is especially interesting, because all these special dispositions form a scarce and perhaps the only specimen of the military architecture in the middle ages.
The two doors of the large flight of steps and the two north and south entrances to the Barbican were each closed by only one leaf, of the same size as the openings, and which was horizontally moved and worked by a particular system which is explained by the exceptional situation of Mont Saint-Michel the edifices as well as the works of which are placed one over the other and are joined together only by a series of flight of steps and slopes of various kinds.
The leaves of the doors turned on their horizontal axis resting on projecting doorposts, established inside of the doors; they were opened in a parallel manner
with the declivity of the flight of steps and at the least alert, it was easy to let them down very quickly, for they were pulled down by the weight itself of the lower part provided with heavy iron-works; they were kept shut by bolts, laterally fixed on the interior part of the leaves: the staples of the locks of which are still seen sealed in the posts of the doors.
The shut leaves made great opposition to the attacks from the exterior, because supported by the lateral rebates and the interior steps, directed against the pres-sure, they could not be broken through or driven up except after long attempts: by these means they defied any surprise.
The skilful means used to protect the approches of the Barbican of the Ghatelet, as well as the obstacles accumulated on the stairs which lead to its doors, detained the assailant and counteracted the attempts which he made to seize, by an attack with open force, upon the exterior works of the gate of the Fortress-Abbey.
Therefore, thanks to its protectors and principally to its abbots, clever architects as well as vigilant captains , the military work of whom completed the natural defences which rendered it inexpugnable, the Abbey had the glorious and rare honour of resisting victoriously the violent assaults of the Enghshmen as well as the perfidious artifices of the Huguenots, and has never been the prey of the enemies of France and of the catholic religion.
The fronts of the edifices built from the XIII to the XVth century, as well as those of the Barbican.