Human beings have long felt the need for security against attack by members of their own species, and from very early times natural defensive sites such as peninsulas and hilltops have been strengthened with ramparts,ditches and timbering. These sites served as places of refuge in times of danger, and in some instances developed into permanent settlements, at which point they might be classified as castles, or even if sufficiently populated, towns.
The defining feature of a castle is that it is a fortified dwelling,habitable and defensible against a reasonably sustained onslaught, and therefore distinguishable from barracks, citadels and other more or less fortified places.Whether or not they should be defined as castles, the many fortified places, or duns in Iron Age Scotland merit a place in any survey.While most Britons were still constructing earthworks for defensive purposes, people in the far north were already building in stone, partly at least because there was so little timber available in the region.As a result, the earliest British dwellings to have survived are stone houses in the Orkney Islands, in the heavy forested south, only powerful religious impulses justified buildings in stone- as Stonehenge=nd both ordinary dwellings and any defensive works made of wood have simply rotted away. In the years following the Conquest the Normans tried to ensure their security by building castles at strategic points all over England.From his castle the baron could dominate the surrounding countryside and overawe the villagers on his manor. In the first instance, almost all these castles were built of timber. The main reason for this was speed; The Normans needed adequately secure defences as quickly as possible. The use of stone demanded time, resources, skill and transport facilities, whereas the available saxon labor force- accustomed to working with wood, and to banking and ditching- could build a motte-and-bailey castle in a remarkable short time.
The Motte-and-Bailey Castle:
The Norman Conquerors built their castles in locations where they could keep control of the local populations of Saxons or at important locations such as river crossings or on key roads. Many motte and bailey castles were built on the border with Wales to try and keep the Welsh at bay. The advantage of this type of castle was that it was quick to construct. Making a fortification from wood was much easier than making one of stone. During the early part of the Norman invasion, the designers of these early castles built wooden towers on the top of a mound for protection. They either used an existing mound where one was available or more usually built their own mound on which they then constructed the tower or keep. At the top of the mound, around its edge, they build a wooden wall or palisade. The mound, now known as a motte, was usually surrounded by a ditch which in some cases could be filled with water. At the foot of the motte was built a normally oval-shaped enclosure known as a bailey that had a palisade and a ditch of its own. The motte was usually placed to one side of the bailey rather than in the centre. Some castles had more than one bailey. An example of this type can be seen at Windsor which has the motte at the centre of two large baileys.
Keeps and Halls
For King William and his powerful supports, timber construction was at best a temporary expedient, and in some instances they dispensed with it altogether. The characteristic Norman stone castle was a keep, generally square or rectangular tower whose chief defensive feature was its mighty walls, many feet thick: to build it involved quarrying substantial quantities of stone and transporting it to the site, often over long distances. Most of the early keeps were located at points where a Norman military presence was of vital strategic importance.In 1078 William the Conqueror began replacing his earth-and-timber castle in the south-east corner of London with a stone keep tucked into the city walls. This, the White Tower, received its name from being regularely repainted in that color, perhaps to remind Londoners of their master’s might; it forms the earliest part of what is now the Tower of London.It was built for William by Gundulf, Bishop of Rochester, who later supervised the construction of the even bigger royal keep at Colchester. Even before Gundulf started the White Tower, the Breton earl , Alan the Red, had begun Richmond Castle to strengthen the Norman grip on the rebellious North; while other trusted Lords built castles at Chepstow and Ludlov to hold the marches against the turbolent Welsh.