In an effort to further unify both economically and politically, the major powers of Europe developed the Treaty on European Union, known more informally as the Maastricht Treaty. Among its major provisions was the creation of a common currency, which came to be known as the Euro, which would replace the Eurozone member states’ currencies.

On this day, January 4th, in 1999, the new Eurozone officially introduced the Euro into the financial markets. Eleven European Nations took part, including France, Germany and Spain. One of the notable holdouts was the UK, which feared a loss of sovereignty – as well as because British public opinion had consistently opposed the Euro.

A twelfth EU member, Greece, wanted to join the Eurozone initially, but was rejected because it didn’t meet the financial stability criteria. Greece was accepted in 2000 and admitted into the following year, provided that they would carry out several mandated financial reforms.