Monetary policy diverged increasingly, until the union was formally terminated in 1931. As a third example, let’s have a brief look at the German Monetary Union of 1871. The ground for that currency union was well prepared. First, the German Customs Union had already created a common market, although that had been hampered by the existence of disparate coinage systems.
Labor mobility in the common market was relatively high. Second, Germany had been united politically under the lead of Prussia. The Reichsbank Act of 1875 then established a unified central bank to complete the German Monetary Union. It introduced the German "Mark" currency one year later.