History of European integration
From the European Coal and Steel Community (1951) to today’s European Union. The EEC, the European Communities and the European Union are distinct stages: we name the right one at each date.
The European Union: from 6 to 27 members
Until 3 October 1990 only West Germany (FRG) was a member. East Germany (GDR), in grey, joined the Communities through reunification. Approximate outline (present-day Länder); other borders as today.
2026
27 member states
European Union
Last change: 2020
All dates 45
Schuman Declaration
Othereuroparl.europa.eu
Treaty of Paris (ECSC) signed
Treaty signedeuroparl.europa.eu
ECSC Treaty enters into force
Treaty in forceeuroparl.europa.eu
Treaties of Rome (EEC, Euratom) signed
Treaty signedeuroparl.europa.eu
Treaties of Rome enter into force
Treaty in forceeuroparl.europa.eu
Merger Treaty signed (Brussels)
Treaty signedeuroparl.europa.eueur-lex.europa.eu
Merger Treaty enters into force
Treaty in forceeur-lex.europa.eu
Denmark, Ireland and the United Kingdom join
Enlargementeuropa.eu
First direct elections to the European Parliament (7-10 June 1979)
Greece joins
Enlargementeuropa.eu
Greenland leaves the European Communities
Withdrawaleur-lex.europa.eu
Schengen Agreement signed
Treaty signedeur-lex.europa.eu
Spain and Portugal join
Enlargementeuropa.eu
Single European Act signed (nine states; Denmark, Italy, Greece on 28 Feb 1986)
Treaty signedeuroparl.europa.eu
Single European Act enters into force
Treaty in forceeuroparl.europa.eu
Convention implementing the Schengen Agreement signed
Treaty signedeur-lex.europa.eu
Maastricht Treaty (Treaty on European Union) signed
Treaty signedeuroparl.europa.eu
Maastricht Treaty enters into force: the European Union is created
Treaty in forceeuroparl.europa.eu
Austria, Finland and Sweden join
Enlargementeuropa.eu
Schengen Convention applied; border controls lifted between first seven states
Treaty in forceeur-lex.europa.eueur-lex.europa.eu
Treaty of Amsterdam signed
Treaty signedeuroparl.europa.eu
Euro introduced in 11 countries (book money)
Currencyecb.europa.eu
Treaty of Amsterdam enters into force
Treaty in forceeuroparl.europa.eu
Treaty of Nice signed
Treaty signedeuroparl.europa.eu
Euro banknotes and coins enter circulation
Currencyecb.europa.eu
Treaty of Nice enters into force
Treaty in forceeuroparl.europa.eu
Ten countries join (largest enlargement)
Enlargementeuropa.eu
Treaty establishing a Constitution for Europe signed (Rome)
Treaty signedeur-lex.europa.eu
French referendum rejects the Constitutional Treaty
Othereuroparl.europa.eu
Dutch referendum rejects the Constitutional Treaty
Othereuroparl.europa.eu
Bulgaria and Romania join
Enlargementeuropa.eu
Treaty of Lisbon signed
Treaty signedeur-lex.europa.eu
Treaty of Lisbon enters into force
Treaty in forceeur-lex.europa.eueuroparl.europa.eu
UK referendum votes to leave the EU
Otherconsilium.europa.eu
United Kingdom leaves the EU
Withdrawalconsilium.europa.eu
End of the Brexit transition period
Othereuropa.eu
Croatia adopts the euro and joins Schengen
Currencyeuropa.euecb.europa.eu
European Parliament elections (6-9 June 2024), 720 MEPs
Electioneuroparl.europa.eu
Second von der Leyen Commission and European Council President António Costa take office
Bulgaria and Romania fully in Schengen (land border checks lifted)
Bulgaria adopts the euro (21st euro area member)
Currencyecb.europa.euecb.europa.eu
EU and Switzerland sign package of bilateral agreements ('Bilaterals III')
Othereuropa.eda.admin.ch
Ukraine and Moldova open first negotiating cluster (fundamentals)
Compare two periods
Two maps side by side, any two years
Members, euro area and Schengen on two dates, with the list of changes in between.