wood. The wooden erections have now of course disappeared, but the enclosing ditches and mounds and the central motte may still be traced.
The wooden castle on the top of the motte, with the steps leading up to it, may be seen depicted in the Bayeux Tapestry, and other mediæval designs.
In the hilly parts of the country the castles were naturally situated on a height, or the edge of a cliff, and the shape of the enceinte was necessarily regulated by the configuration of the ground, its slopes or precipices being made available for defence. The hall or keep was set either on the most elevated point, or so placed as to defend the weakest places. In mountainous districts, where stone abounded, it naturally soon came to replace wood as the building material. The space afforded by special sites was frequently not large enough to contain all the dependencies. In such cases the various out-buildings were erected at the base of the hill or escarpment, and were included within an outer enclosing wall, or palisade and ditch, thus forming a second court or basse-cour. The keep was usually so placed as to command and defend these out-buildings.
It was soon found that the keep in the centre of the court was not conveniently situated for defence, and that it was better placed next the outer wall, so as to allow the garrison to make sorties and take the enemy by surprise, and also to permit the garrison in case of need to escape. We find the keep thus placed from the eleventh century. This was also the case in the fortresses composed of earthworks, the motte being usually placed on one of the lines of the enclosing mounds.
The Normans adopted a similar arrangement of their defences from the eleventh century. Till nearly the middle of that century the fortresses of Normandy consisted entirely of earthworks, with wooden palisades and buildings, but from that date square towers or keeps began to be built. The Normans devoted their attention chiefly to making these keeps of great strength, while the outworks were of comparatively small importance, and did not include the extensive courtyards common in other parts of Frankia. One reason for this may have been that the Normans worked together, and placed their castles so as to occupy strategic points, and protect one another and the country round about them. The Frank castles, on the other hand, were isolated and independent, each being constructed for the defence of the lord and his retainers, with their families and possessions. The latter castles were therefore necessarily of great extent, and the outer works are of first importance.
The first idea of the Norman keep was probably a wooden block-house for the protection of valuables, booty, etc., defended with ditches or earthworks. When the Normans had more thoroughly established themselves in the country, they began to build their castles of stone, and by the time of the Conquest of England the north of France was well supplied with castles, some consisting of the earthworks above referred to, and
