The fact that the transition passed off so smoothly was the result of a long and well-prepared process - entailing a great deal of effort - and of the excellent technical preparations made by the European institutions - in particular the ECB and the national central banks involved. Undoubtedly, the start of monetary union constitutes a historic step in the process of European integration.
But it will also have far-reaching external implications. It will constitute a major change in the international financial system. II In order to be able to join EMU, most EU member states had to make profound monetary and economic policy adjustments. Only those which met the four well-known convergence criteria of the Maastricht Treaty were allowed to become a “euro country”.