The euro was launched on 1 January 1999, when it became the currency of more than 300 million people in Europe. For the first three years it was an invisible currency, only used for accounting purposes, e.g. in electronic payments. Euro cash was not introduced until 1 January 2002, when it replaced, at fixed conversion rates, the banknotes and coins of the national currencies like the Belgian franc and the Deutsche Mark.
Today, euro banknotes and coins are legal tender in 19 of the 28 Member States of the European Union, including the overseas departments, territories and islands which are either part of, or associated with, euro area countries. These countries form the euro area. The micro-states of Andorra, Monaco, San Marino and Vatican City also use the euro, on the basis of a formal arrangement with the European Community. Montenegro and Kosovo likewise use the euro, but without a formal arrangement. Cash payments are now made in the same currency by 340 million people — euro banknotes and coins have become a tangible symbol of European integration.
All EU countries, except Denmark and the United Kingdom, which have an opt-out, are expected to join the monetary union and to introduce the euro as soon as they fulfil the convergence criteria.
The euro came into existence on 1 January 1999. It had been a goal of the European Union (EU) and its predecessors since the 1960s. The Maastricht Treaty entered into force in 1993 with the goal of creating economic and monetary union by 1999 for all EU states except the UK and Denmark (even though Denmark has a fixed exchange rate policy with the euro).
In 1998 eleven member states of the European Union had met the euro convergence criteria, and the eurozone came into existence with the official launch of the euro (alongside national currencies) on 1 January 1999 the euro was introduced virtually, and in 2002 notes and coins began to circulate. They are issued by the national central banks of the Eurosystem or the European Central Bank. The euro rapidly took over from the former national currencies and slowly expanded around the European Union. Greece qualified in 2000, was admitted on 1 January 2001 before physical notes and coins were introduced. Between 2007 and 2015, seven new states acceded.
In 2009 the Lisbon Treaty formalized its political authority, the Eurogroup, alongside the European Central Bank.