On the 25th March 1957 the Treaty of Rome, which laid the foundations for the European Economic Community, was signed by Belgium, France, Italy, Luxembourg, the Netherlands and West Germany. The EEC, sometimes referred to as the Common Market, was formally established on the 1st January 1958 and survived, with some changes under the Maastricht Treaty, until 2009 when it was absorbed into the European Union.
The aim of the EEC was to establish economic integration between its members, such as a common market and customs union. However in reality the EEC operated beyond purely economic issues since it included organisations such as the European Atomic Energy Community that sought to generate and distribute nuclear energy to its member states.
The EEC was preceded by the European Coal and Steel Community, which came into force in 1952. The ECSC sought to amalgamate European coal and steel production in order to reconstruct Europe after the devastation of the Second World War and reduce the threat of a future conflict by establishing mutual economic reliance. Within just three years the idea of a customs union was being discussed, with the 1956 Intergovernmental Conference on the Common Market and Euratom establishing the parameters for the Treaty of Rome.
Over time the EEC expanded its membership with Denmark, Ireland and the United Kingdom joining in 1973; the 1980s saw the addition of Greece, Spain and Portugal. With the creation of the European Union in 1993 and its absorption of the EEC in 2009 the union currently contains 28 states, the most recent member being Croatia in July 2013.