The euro became the official accounting currency of participating countries in 1999.
On 1 January 1999, the euro was introduced as a virtual currency for electronic payments, banking and financial accounting in the first euro-area countries. National currencies continued to circulate as physical cash during the transition period.
Euro banknotes and coins entered circulation on 1 January 2002. This created a common source of confusion: 1999 marks the currency's launch for financial and accounting purposes, while 2002 marks the arrival of euro cash in daily life.
The euro is issued and managed within the Eurosystem, consisting of the European Central Bank and the central banks of euro-area members. Membership has expanded since the original launch, although not every European Union country uses the currency.