This system of popular election seems to have worked admirably, for in the centuries that followed, the rulers of the community were generally men of remarkable character and great ideals. About fifty years before the Conquest of England by Duke William, the abbot of that time, Hildebert II., commenced work on the prodigious series of buildings that still crown the rock. His bold scheme of building massive walls round the highest point, in order to make a lofty platform whereon to raise a great church, was a work of such magnitude that when he was gathered to his fathers the foundations were by no means complete. Those who came after him however, inspired by the great idea, kept up the work of building with wonderful enthusiasm. Slowly, year by year, the ponderous walls of the crypts and undercrofts grew in the great space which it was necessary to fill. Dark, irregularly built chambers, one side formed of the solid rock and the others composed of the almost equally massive masonry, grouped themselves round the unequal summit of the mount, until at last, towards the end of the eleventh century, the building of the nave of the church was actually in progress. Roger II., the eleventh of the abbots, commenced the buildings that preceded the extraordinary structure known as La Merveille. Soon after came Robert de Torigny, a pious man of great learning, who seems to have worked enthusiastically. He raised two great towers joined by a porch, the hostelry and infirmary on the south side and other buildings on the west. Much of this work has unfortunately disappeared. Torigny's coffin was discovered in 1876 under the north-west part of the great platform, and one may see a representation of the architect-abbot in the clever series of life-like models that have been placed in the museum. The Bretons having made a destructive attack upon the mount in the early years of the thirteenth century and caused much damage to the buildings, Jourdain the abbot of that time planned out "La Merveille," which comprises three storeys of the most remarkable Gothic halls. At the bottom are the cellar and almonry, then comes the Salle des Chevaliers and the dormitory, and above all are the beautiful cloisters and the refectory. Jourdain, however, only lived to see one storey completed, but his successors carried on the work and Raoul de Villedieu finished the splendid cloister in 1228. Up to this time the island was defenceless, but during the abbatiate of Toustain the ramparts and fortifications were commenced. In 1256 the buildings known as Belle-Chaise were constructed. They contained the entrance to the abbey before the chatelet made its appearance. After Toustain came Pierre le Roy who built a tower behind Belle-Chaise and also the imposing-looking chatelet which contains the main entrance to the whole buildings. The fortifications that stood outside this gateway have to some extent disappeared, but what remain are shown in the accompanying illustration.