projecting parlour and chapel is not sufficiently explicit, and his admiration may have magnified the proportions of the building. His description, however, is of great service when applied to the tower donjon of stone, the arrangements of which it serves to explain. Here, again, the fortress was clearly designed as a dwelling house: the supply of rooms, if it is not exaggerated, was quite remarkable for the age. The _motte_ or donjon—Lambert gives it these alternative names—rose in the middle of a marsh, which Arnould converted into a lake or moat by forming sluices: his mill was near the first sluice. No definite description is left of the defences of the bailey in a castle of this date. There is no doubt, however, that the scarp, or encircling bank of earth, was protected, like the summit of the mount, by a hedge or palisade of the traditional type. Such hedges were the normal defence of any kind of stronghold: the edict of Pistes ordered the destruction of all unlicensed _castella, firmitates, et haias_—castles, strong dwellings, and hedges. In 1225 Henry III. ordered the forester of Galtres to supply the sheriff of Yorkshire with timber for repairing and making good the breaches of the palisade (_palicii_) of York castle. The “houses” and “bridge” of the same castle—that is, the buildings within the bailey, and the drawbridge by which the bailey was entered across the ditch, were also of timber. As late as 1324 the stockade on the mount was still of wood, surrounding the stone donjon of the thirteenth century.[59] This is an interesting example of the survival, until a late date, of primitive fortification in a strong and important castle. There is abundant evidence, in fact, that the Norman engineer put his trust, not in stone, but in his earthen rampart and its palisades. When, about 1090, the freebooter Ascelin Goël got possession of the castle of Ivry, he enclosed it “with ditches and thick hedges.”[60] In 1093, Philip I. of France and Robert of Normandy took the part of William of Breteuil, the dispossessed lord of Ivry, and laid siege to the fortified town and castle of Bréval (Seine-et-Oise). With the aid of a siege engine, constructed by Robert of Bellême, they were able to destroy the rampart and encircling hedges.[61] Bréval was in a wooded and remote district, where stone would have been hard to obtain in any case. The grand necessity, in places which were in danger of constant attack, was to provide them with adequate defences which could be constructed in the shortest time possible.