A simple fortification consisted of two parts: a natural or artificial mound (motte) with a wooden tower or keep on top, and a larger area at the foot of the mound enclosed by palisades, (and later by walls and towers of masonry), called a bailey. The bailey was used for stores and huts. This outer walled space sometimes had a ditch in front of it which might be flooded to make moat.
These ‘motte and bailey’ castles were built mostly in France during the tenth century, but the building of this type of private fortress spread over western Europe in the following century. In the Middle Ages land was owned under the feudal system. Princes and nobles kept private armies to enforce power over their own domains. War was constantly breaking out between local lords, and a fortified dwelling was essential. These castles were simple but effective. They could withstand a siege. Gunpowder had not yet been invented and success was achieved by starvation – or treachery. They offered a refuge for neighbouring villagers and their flocks.
Little trace remains today of the wooden ‘motte and bailey’ castles, but many with stone keeps are still standing. They were tall, square buildings, with a single room on each floor. Sometimes, for greater protection, and outside stair led to an entrance on the first floor.