Brussels and the European Union a provisional seat, though with the Common Assembly in Strasbourg as that was the only city with a large enough hemicycle (the one used by the Council of Europe). This agreement was temporary, and plans were set to relocate the institutions to Saarbrücken which would serve as a "European District", but this did not occur. The 1957 Treaties of Rome established two new communities, the European Economic Community (EEC) and the European Atomic Energy Community (Euratom). These shared the Assembly and Court of the ECSC but created two new sets of Councils and Commissions (equivalent to the ECSC's High Authority).
History of the European Communities (1958–72) Historical Archives of the European Union in Florence History of the European Communities (1958–72) The history of the European Communities between 1958 and 1972 saw the early development of the European Communities. The European Coal and Steel Community (ECSC) had just been joined by the European Atomic Energy Community (Euratom) and the European Economic Community (EEC), the latter of which soon became the most important. In 1967 the EEC's institutions took over the other two with the EEC's Commission holding its first terms under Hallstein and Rey. In 1958 the Committee of Permanent Representatives (COREPER) was established. On 19 March