Who and which country started with the euro?

The euro was introduced by 11 of the 15 member states of the European Union on January 1, 1999. The founding countries were Belgium, Germany, Greece, Spain, France, Ireland, Italy, Luxembourg, the Netherlands, Austria, and Portugal. These nations aimed to create a unified currency to enhance economic stability and integration within Europe. The physical euro banknotes and coins were later introduced on January 1, 2002.