Despite their imposing positions and solid construction, these early Norman castles with their wooden palisades and keep were more vulnerable to attack than castles built from stone. And in the tumultuous years following the conquest rebellions and uprisings were frequent, and castles were often under attack.

Norman castles were exceptionally effective tools of military and political control, fundamentally altering the landscape of England following the conquest in 1066. Their primary effectiveness lay in their rapid construction and psychological dominance; the initial "motte-and-bailey" designs could be erected in just weeks using local timber and earth, providing an immediate stronghold for Norman garrisons in hostile territory. These structures acted as "force multipliers," allowing a relatively small number of Norman knights to dominate large, rebellious Anglo-Saxon populations. Architecturally, the transition to stone "keeps"—such as the White Tower in London—made these fortifications virtually impregnable to contemporary siege technology. The vertical design provided defenders with a massive tactical advantage, while the thick walls and layered defensive positions made a direct assault suicidal. Beyond physical defense, these castles served as administrative hubs for the new feudal system, symbolizing the permanent and unshakeable authority of the Norman elite. Their effectiveness is proven by the fact that they suppressed almost all local resistance within a generation, creating a centralized network of power that defined the English Middle Ages.