1993   The Maastricht Treaty takes effect, officially establishing the European Union.

1994   Finland votes to join the European Union.

1994   Voters in Sweden decide to join the European Union.

1995   Austria, Finland and Sweden join the European Union.

1999   The Euro currency is introduced in eleven of the European Union countries.

2002   The former national currencies of all European Union member countries officially cease to be legal tender in their respective nations.

2003   Estonia votes to join the European Union in a national referendum.

2004   Ten nations are added to the European Union including Poland, Lithuania, Latvia, Estonia, the Czech Republic, Slovakia, Slovenia, Hungary, Malta and Cyprus. The expansion is the largest expansion to date.

2004   In Rome, Italy, a treaty establishing the first Constitution for Europe was officially signed by the representatives of the then twenty-five Member States of the European Union.

2005   Spain votes to ratify the constitution of the European Union by a 4-1 margin. Spain was the first of the EU countries to vote in a referendum on the EU constitution.

2005   Voters in France reject the proposed constitution of the European Union. France is the first European country to fail to ratify the constitution.

2005   The Netherlands becomes that second country to reject the proposed constitution of the European Union.

2005   Luxembourg votes to accept the European Union constitution.