European Union and West Germany signed the Treaty of Rome, which created the European Economic Community (EEC) and established a customs union. They also signed another pact creating the European Atomic Energy Community (Euratom) for co-operation in developing nuclear energy. Both treaties came into force in 1958. The EEC and Euratom were created separately from the ECSC, although they shared the same courts and the Common Assembly. The EEC was headed by Walter Hallstein (Hallstein Commission) and Euratom was headed by Louis Armand (Armand Commission) and then Étienne Hirsch. Euratom was to integrate sectors in nuclear energy while the EEC would develop
European Economic Community compromise was reached with the Luxembourg compromise on 29 January 1966 whereby a gentlemen's agreement permitted members to use a veto on areas of national interest. On 1 July 1967 when the Merger Treaty came into operation, combining the institutions of the ECSC and Euratom into that of the EEC, they already shared a Parliamentary Assembly and Courts. Collectively they were known as the "European Communities". The Communities still had independent personalities although were increasingly integrated. Future treaties granted the community new powers beyond simple economic matters which had achieved a high level of integration. As it got closer to