Follow this timeline to learn about the series of steps over decades that led to the creation of the European Union.
- 1923: Pan European Union society formed; supporters include Konrad Adenauer and Georges Pompidou, later leaders of Germany and France.
- 1942: Charles de Gaulle calls for a union.
- 1945: World War II ends; Europe is left divided and damaged.
- 1946: European Union of Federalists forms to campaign for a United States of Europe.
- September 1946: Churchill calls for a United States of Europe based around France and Germany to increase the chance of peace.
- January 1948: Benelux Customs Union formed by Belgium, Luxembourg, and Netherlands.
- 1948: Organisation for European Economic Co-operation (OEEC) created to organize the Marshall Plan; some argue this is not unified enough.
- April 1949: NATO forms.
- May 1949: Council of Europe formed to discuss closer co-operation.
- May 1950: Schuman Declaration (named after the French Foreign Minister) proposes French and German coal and steel communities.
- April 19, 1951: European Coal and Steel Community Treaty signed by Germany, France, Ireland, Luxembourg, Belgium, and Netherlands.
- May 1952: European Defence Community (EDC) Treaty.
- August 1954: France rejects the EDC treaty.
- March 25, 1957: Treaties of Rome signed: creates Common Market / European Economic Community (EEC) and European Atomic Energy Community.
- January 1, 1958: Treaties of Rome come into effect.
- 1961: Britain tries to join the EEC but is rejected.
- January 1963: Franco-German Treaty of Friendship; they agree to work together on many policy issues.
- January 1966: Luxembourg Compromise gives majority vote on some issues, but leaves national veto on key areas.
- July 1, 1968: Full customs union created in the EEC, ahead of schedule.
- 1967: British application again rejected.
- December 1969: Hague summit to “relaunch” the Community, attended by heads of state.
- 1970: Werner Report argues economic and monetary union possible by 1980.
- April 1970: Agreement for EEC to raise own funds through levies and customs duties.
- October 1972: Paris Summit agrees on plans for the future, including economic and monetary union and ERDF fund to support depressed regions.
- January 1973: UK, Ireland, and Denmark join.
- March 1975: First meeting of the European Council, where heads of state gather to discuss events.
- 1979: First direct elections to European Parliament.
- March 1979: Agreement to create the European Monetary System.
- 1981: Greece joins.
- February 1984: Draft Treaty on European Union produced.
- December 1985: Single European Act agreed; takes two years to ratify.
- 1986: Portugal and Spain join.
- July 1, 1987: Single European Act comes into effect.
- February 1992: Maastricht Treaty / Treaty on European Union signed.
- 1993: Single Market begins.
- November 1, 1993: Maastricht Treaty comes into effect.
- January 1, 1995: Austria, Finland, and Sweden join.
- 1995: Decision taken to introduce the single currency, the Euro.
- October 2, 1997: Treaty of Amsterdam makes minor changes.
- January 1, 1999: Euro introduced in eleven counties.
- May 1, 1999: Treaty of Amsterdam comes into effect.
- 2001: Treaty of Nice signed; extends majority voting.
- 2002: Old currencies were withdrawn, 'Euro' becomes the sole currency in the majority of EU; Convention on the Future of Europe created to draw up a constitution for larger EU.
- February 1, 2003: Treaty of Nice comes into effect.
- 2004: Draft constitution signed.
- May 1, 2004: Cyprus, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovak Republic, Czech Republic, Slovenia join.
- 2005: Draft constitution rejected by voters in France and the Netherlands.
- 2007: Lisbon Treaty signed, this modified the constitution until it was deemed a sufficient compromise; Bulgaria and Romania join.
- June 2008: Irish voters reject the Lisbon Treaty.
- October 2009: Irish voters accept the Lisbon Treaty.
- December 1, 2009: Lisbon Treaty comes into effect.
- 2013: Croatia joins.
- 2016: United Kingdom votes to leave.