2004 enlargement of the European Union

Expansion of the EU EU member states in 2004 New EU member states admitted in 2004 Part of a series on the History of theEuropean Union Timeline Pre-1948 ideas 1948–1957 1958–1972 1973–1993 1993–2004 2004–present Organisation European Communities (1958–2009) European Coal and Steel Community (1952–2002) European Economic Community (1958–1993) European Atomic Energy Community (1958–present) European Community (1993–2009) Justice and Home Affairs (1993–2003) Police and Judicial Co-operation in Criminal Matters (2003–2009) Common Foreign and Security Policy pillar (1993–2009) Western European Union (1954–2011) Western Union (1948–1954) Treaties Treaty of Paris 1951 Treaty of Rome 1957 Merger Treaty 1965 Single European Act 1986 Maastricht Treaty 1992 Treaty of Amsterdam 1997 Treaty of Nice 2001 Treaty of Lisbon 2007 Commissions Hallstein Commission 1958 Rey Commission 1967 Malfatti Commission 1970 Mansholt Commission 1972 Ortoli Commission 1973 Jenkins Commission 1977 Thorn Commission 1981 Delors Commissions I–III 1985 Santer Commission 1994 Prodi Commission 1999 Barroso Commission I & II 2004 Juncker Commission 2014 Von der Leyen Commission I 2019 Von