Power increasingly was centralized among the 7000 aristocrats, who resided in the national capital of Berlin and neighboring Potsdam. Berlin's rapidly increasing rich middle-class copied the aristocracy and tried to marry into it. A peerage could permanently boost a rich industrial family into the upper reaches of the establishment. However, the process tended to work in the other direction as the nobility became industrialists. For example, 221 of the 243 mines in Silesia were owned by nobles or by the King of Prussia himself.