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
Merger Treaty common institutions (prior to this treaty, they already shared a Parliamentary Assembly and Court of Justice) and were together known as the European Communities. This treaty is regarded by some as the real beginning of the modern European Union. This treaty was abrogated by the Amsterdam Treaty signed in 1997: Merger Treaty The Merger Treaty (or Brussels Treaty) was a European treaty which combined the three executive bodies of the European Coal and Steel Community (ECSC), European Atomic Energy Community (Euratom) and the European Economic Community (EEC) into a single institutional structure. The treaty was signed in Brussels on 8