Warfare had become endemic in eleventh- and twelfth-century Europe. Castle building used up the resources of the land as every landholder from the ki… - Marilyn Stokstad

Wherever they went, William and his Norman lieutenants built castles. About 170 great vassals came to England with William. When the king rewarded his followers with grants of land, they also assumed the responsibility for its defense, so each built one or more castles. William and his men had several reasons for building castles. As hostile invaders they had to fortify their dwellings and camps in order to hold the territory and provide security for themselves. Their castles also secured borders and coastlines against other invaders and controlled the movement of people and goods at key transportation centers such as fords, bridges, and passes and along major roads.

Women played a greater role than might be expected in this elite warrior society, as heiresses and chatelaines in charge of castles (see Documents 44–53). Since land was the basis of status and power, estates were kept intact by being passed on to the oldest son rather than being divided among all the children. In spite of high infant mortality and short life expectancies, a family hoped that at least one son survived to inherit lands and titles. Younger sons hoped to gain an estate of their own by marrying an heiress.

Castles were more than military posts; they were the centers of political and economic power. As government headquarters they were built to impress the local population as well as visitors and rivals. While power was spread among great tenants-in-chief in a system of delegated government, castles in each territory were places where local lords collected taxes, settled disputes, and administered justice.