1951- Treaty of Paris establishes the European Coal and Steel Community (ECSC) to create a common approach to the coal and steel resources of six countries - Germany, France, Italy, Belgium, the Netherlands, and Luxembourg.
1957 - Two treaties of Rome involving the same six. One creates the European Economic Community (EEC) with a common market based on four freedoms: freedom of movement of goods, services, people and capital.
The other is Euratom, establishing a common approach to nuclear energy research.
1965 - Treaty merges ECSC, EEC, and Euratom.
1972 - Accession treaty for Ireland, UK, Denmark and Norway (The latter subsequently rejects accession in referendum)
1980 - Greek accession.
1985 - Spanish and Portuguese accession.
1986 - Single European Act adopts major package to complete single market and exteds the use of qualified majority voting.
1992 - Treaty on European Union (Maastricht) sets up path to monetary union, establishes formal basis for common foreign and security policy and justice and home affairs decision-making, and extends use of majority voting.
1995 - Finland, Austria and Sweden accede.