The American banking system was in the past characterised by great fragmentation of the commercial banking sector, comprising thousands of mostly small banks - and a prolonged dispute over the need of a central bank, which ended only with the creation of the Federal Reserve System in 1913. Before reaching the position it enjoyed throughout the 20th century, the dollar was not a particularly strong currency. After World War II, as the American economy gradually assumed a leading role in the world, the Federal Reserve System was by default vested with responsibility for the condition of the world's economy as well as that of America.