Most monetarists opposed the gold standard because they believed that the limited supply of gold would cause the amount of money in the system to stagnate, resulting in inflation. Monetarists believe that inflation should be controlled by the money supply, which is impossible to do under the gold standard unless gold is continuously mined. The most well-known monetarist is Milton Friedman. Former Federal Reserve Chair Alan Greenspan and former British Prime Minister Margaret Thatcher are among the monetarists.