Ninth-century castles were relatively small and simple affairs designed to safeguard a relatively small number of people and intended as a refuge dur… - Marilyn Stokstad

When a strong central authority protects borders and reduces internal crime, people have little need for fortified dwellings, although the rulers may build walls and towers to define legitimate residents and defend the country against external threats. When central authority breaks down, however, individuals are more likely to fortify their homes. The presence of castles in the landscape indicates a decline in stability and peace.

A sharp contrast existed between the upper classes who constantly moved from manor to manor and the peasants who were tied to the land and lived in agricultural villages outside the castle walls. Yet economic opportunities expanded for both groups.

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.