Treaties of the European Union the Functioning of the European Union (originally signed in Rome in 1957 as the Treaty establishing the European Economic Community, aka The Treaty of Rome), lay out how the EU operates, and there are a number of satellite treaties which are interconnected with them. The treaties have been repeatedly amended by other treaties over the 65 years since they were first signed. The consolidated version of the two core treaties is regularly published by the European Commission. The two principal treaties on which the EU is based are the Treaty on European Union (TEU; Maastricht Treaty, effective since 1993) and
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