Castles were private homes built to fight from, not just hide in
Historians define a castle narrowly: a lord's private fortified residence. That rules out walled cities, Anglo-Saxon burhs and most things crusaders called castles. It also explains why castles were aggressive tools, raiding bases planted in hostile country, and why they faded once cannon made them miserable places to live.
European castles emerged in the ninth and tenth centuries, after the Carolingian Empire broke up and its lands fell to individual lords and princes. Each noble built to dominate the surrounding district, launching raids from the walls as well as sheltering behind them. Castles also housed administration and displayed power. Town castles watched over residents and key roads, while rural ones tended to sit beside mills, good farmland or water.
William the Conqueror used them to hold England. The word itself, from Latin castellum, a diminutive of castrum or fortified place, entered English shortly before 1066 because such buildings were new there. Between 1066 and 1087 William founded 36 castles, among them Warwick, which guarded against rebellion in the Midlands. Many northern European castles began as earth and timber and were rebuilt in stone later, and the earliest leaned on natural defences and a central keep rather than towers.
In the late twelfth and early thirteenth centuries designers grew more systematic. Towers multiplied to allow flanking fire, and many new castles were polygonal or concentric, with rings of defences inside one another that could all fight at once. Crusader experience and old Roman forts both fed these ideas. Some features drifted from war to display: moats became status symbols, and grand castles might have long winding approaches meant to impress.
Gunpowder reached Europe in the fourteenth century but changed little until the fifteenth, when artillery could smash stone walls. Castles were still built into the sixteenth century, yet the thick defences needed against better cannon made them uncomfortable homes. Their roles split: artillery star forts took over defence with no administrative function, while country houses and chateaux offered comfort without protection. From the eighteenth century a Gothic revival produced mock castles with no military purpose at all.
Source: Castle
