[52] See Part III., "Military Architecture," Abbey of Mont St. Michel.
The Abbey of Tournus was, like Cluny, surrounded by walls connected with the city ramparts.
The Abbey of St. Allyre, in Auvergne, near Clermont, was defended by walls and towers, which seem to have been added to the original structure of the ninth century at some period during the thirteenth, when such fortification of religious houses became necessary.
149. ABBEY OF MONT ST. MICHEL. GENERAL VIEW FROM THE ROCKS OF COUESNON, TAKEN IN 1878, BEFORE THE CONSTRUCTION OF THE DYKE
In many other monasteries a system of defence more or less elaborate was adopted; but the most famous of all the abbeys built by the Benedictines was unquestionably Mont St. Michel, which, for boldness and grandeur of design, is unique among military and monastic monuments from the eleventh to the close of the fifteenth century.
150. ABBEY OF MONT ST. MICHEL. PLAN AT THE LEVEL OF THE GUARD-ROOM, ALMONRY, AND CELLAR
Key to Plan.—A. Tower known as the Tour Claudine. Ramparts. B. Barbican. Entrance to the abbey. B′. Ruin of the stairway known as the Grand Degré. C. Gate-house. D. Guard-room known as Bellechaise. E. Tower known as the Tour Perrine. F. Steward's lodging and Bailey. G. Abbot's lodging. G′. Abbatial buildings. G′. Chapel of St. Catherine. H. Courtyard of the church, great stairway. I. Courtyard of the Merveille. J, K. Almonry, cellar (of the Merveille). L. Formerly the abbatial buildings. M. Gallery or crypt known as the Galerie de l'Aquilon (of the North Wind). N. Hostelry (Robert de Thorigni). O. Passages connecting the abbey with the hostelry. P, P′. Prison and dungeon. R, S. Staircase. T. Modern wall of abutment. U. Garden, terraces, and covered way. V. Body of rock.