others of quadrangular stone-built keeps of the usual well-known Norman type.
In England the Roman influence was much less marked than in Gaul, nearly all the Roman buildings having been destroyed by the Danes in their frequent invasions. A few buildings, however, such as Porchester Castle and Pevensey, still remain, and have been incorporated by the Normans in their castles. The fortresses of the inhabitants up to the eleventh century consisted of earthen mounds and ditches defended by wooden palisades, such as we have seen were common at the same period in the north of France. As in the latter, the hall or castle of the chief was built of wood, and stood on the top of the motte or earthen mound thrown up from the excavation of the ditch surrounding it. It was approached by a straight wooden stair up the slope of the mound, and protected by a drawbridge. There are hardly any traces of building in stone and lime before the Norman Conquest. After that date the erection of Norman keeps became common, but the old wooden towers and other defences were in many cases long retained.
Of Norman keeps there are abundant examples remaining both in Northern France and England. After the Conquest, England was covered with castles of this type, such as Dover, Rochester, Newcastle, the Tower of London, etc. These Norman keeps are always square or rectangular in plan. They have generally flat pilasters on the exterior, the angle pilasters being carried up above the parapet in the form of a square or round turret at each corner. The walls terminate in a crenelated parapet about 2 feet thick and 5 feet high, carried up flush with the face of the wall, and concealing the roof. The roof is of the simple coupled form, with a gable at each end, but the ridge does not rise above the parapet. There are no projecting corbels with machicolations between, the only machicolations used being long openings in the floors. The merlons are broad and the embrasures narrow. The larger keeps have the entrance protected by a forework. This is a building the full width of the keep, and attached to one end of it. It contains a straight stair leading to the true entrance of the keep, which is on the first or second floor. The entrance to the forework is protected by strong oak doors, and bars running into the wall, and sometimes with a portcullis. A tower rises above the doorway, from which missiles may be thrown on an enemy attempting to ascend the straight stair. There are also sometimes intermediate doors with towers above them, and at the top of the stair a vestibule, well defended, and sometimes approached by a moveable bridge. In the upper floors of the forework was occasionally placed the chapel, and the prisons were often under the stair.
The interior of the keep was very simple in its general arrangements. The door on the first or second floor leads into the chief room or hall, where all the garrison lived and slept. From the hall a stair conducts
