Acoercion castle[1][2][3] (German:Zwingburg) orcoercive castle[4][5] was a heavily fortified,medievalcastle built to dominate the surrounding land. Such castles were built mainly in theHigh andLate Middle Ages in order to protect thoseterritories in areas where the population was not assessed as being entirely loyal to the sovereign. Because of the poor infrastructure of medieval Europe, the construction of castles was one of the most important ways of exercising power, which is why it was governed by royal rights (known asregalia). Examples of coercive castles are theMoritzburg in Halle, which was built in the late 15th century, and theAlte Burg inKoblenz.
