European enlargement
In 1952 France , Belgium , Netherlands , West Germany , Luxembourg created the ECSC ( European coal and steel community ) . They signed a treaty in Paris : The European defense community. They put their industries together. In this way, none can on its own make the weapons of war to turn against the other, as in the past.
In 1957 They sign the Treaty of Rome, creating the European Economic Community (EEC).
In 1973 , after the death of the president de Gaulle ( he feared Britain's US influence and vetoed British membership). UK , Ireland and Denmark joined EEC. UK was really industrial (due to economic reasons; Britain was surprised at the success of the EEC and failed to secure a free trade deal with it) and Ireland and Denmark were very agricultural. In 1981 Greece joined EEC because they had oil. Accepting Greece into the EEC meant a great expansion into the Mediterranean. In 1985 Greenland which is a province of Denmark has explicitly voted to leave, departing from the EU's predecessor, the European Economic Community, in 1985. The only member state to hold a national referendum on withdrawal was the United Kingdom in 1975, when 67.2% of those voting voted to remain in the Community.

In 1986 Spain and Portugal joined the EEC. These countries desired to consolidate their new democratic systems by binding themselves into the EEC. However Francois Mitterrand initially opposed their membership fearing they were not ready and it would water the community down to a free trade area. This was also seen as a Mediterranean enlargement. Also they were very important because of fishing and the development of the coast. In 1990 East Germany joined because after the The Fall of the Berlin Wall as they were reunited with West Germany. The Community later became the European Union in 1993. In 1995 Sweden, Finland and Austria joined the EU because contributions from richer countries would help balance the EU budget. In