With regard to the criterion on exchange rate stability, the Maastricht Treaty stipulates that the criterion will be satisfied if “a Member State has respected the normal fluctuation margins provided for by the exchange-rate mechanism (ERM) of the European Monetary System without severe tensions for at least two years before the examination” of compliance with the convergence criteria.
The drachma entered the ERM in March 1998 at a central rate of 357 per ECU, just over 12% below the market rate prevailing at the time. As from January 1999, it joined ERM II at a central rate of 353.109 per euro, with the standard fluctuation band of plus or minus 15%.