On the last day of 1998 the exchange rates of eleven European countries were irrevocably fixed. On 1 January 1999 the euro was established as the single currency of these countries and the European Central Bank started operating and managing the single monetary policy. Greece then joined on 1 January 2002. This represents the first time in history in which a large group of sovereign countries chose to relinquish their national currencies in order to share a new single currency. One of the largest common economic and financial areas in the world thus received an added impetus.