Castle Building (Civ3)/Civilopedia

Castles served many functions in medieval Europe; not only were they formidable defensive positions, but they served as administrative 
and judicial centers and as the seat of a lord's power. Since food and supplies could be stockpiled at castles, castles exerted strong 
influence over very large surrounding territories. Secular lords were not the only ones to build castles; religious officials often did so as 
well, to provide themselves with stronger power bases. Early castles were usually little more than wooden stockades constructed on dirt mounds and 
perhaps surrounded by a shallow trench; by the time of the reign of Edward the Confessor in 13th century England, castle-building had become a much 
more elaborate affair, with hundreds of laborers and specialists constructing huge stone fortresses with intricate defenses in carefully selected 
geographic locations.