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 the European Union, though limited in some areas due to the pillar structure. Despite this, Parliament in particular has gained more power over legislation and security of the Commission. The Court was the highest authority in the law, settling legal disputes in the Community, while the Auditors had no power but to investigate. The EEC inherited some of the Institutions of the ECSC in that the Common Assembly and Court of Justice of the ECSC had their authority extended to the EEC and Euratom in the same role. However the EEC, and Euratom, had different executive bodies to the ECSC.