The German principalities formed a customs union as early as 1818. The three regional groupings (the Northern, Central and Southern) were united in 1833. In 1828, Prussia harmonized its customs tariffs with the other members of the Federation, making it possible to pay duties in gold or silver. Some members hesitantly experimented with new fixed exchange rate convertible currencies. But, in practice, the union already had a single currency: the Vereinsmunze. The Zollverein (Customs Union) was established in 1834 to facilitate trade by reducing its costs. This was done by compelling most of the members to choose between two monetary standards (the Thaler and the Gulden) in 1838. Much as the Bundesbank was to Europe in the second half of the twentieth century, the Prussian central bank became the effective Central Bank of the Federation from 1847 on. Prussia was by far the dominant member of the union, as it comprised 70% of the population and land mass of the future Germany. The North German Thaler was fixed at 1.75 to the South German Gulden and, in 1856 (when Austria became informally associated with the Union), at 1.5 Austrian Florins. This last collaboration was to be a short lived affair, Prussia and Austria having declared war on each other in 1866. Bismarck (Prussia) united Germany (Bavarian objections notwithstanding) in 1871. He founded the Reichsbank in 1875 and charged it with issuing the crisp new Reichsmark. Bismarck forced the Germans to accept the new currency as the only legal tender throughout the first German Reich. Germany's new single currency was in effect a monetary union. It survived two World Wars, a devastating bout of inflation in 1923, and a monetary meltdown after the Second World War. The stolid and trustworthy Bundesbank succeeded the Reichsmark and the Union was finally vanquished only by the bureaucracy in Brussels and its euro. This is the only case in history of a successful monetary union not preceded by a political one. But it is hardly representative. Prussia was the regional bully and never shied away from enforcing strict compliance on the other members of the Federation. It understood the paramount importance of a stable currency and sought to preserve it by introducing various consistent metallic standards. Politically motivated inflation and devaluation were ruled out, for the first time. Modern monetary management was born. Another, perhaps equally successful, and still on-going union - is the CFA franc Zone.