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
Treaty on the Functioning of the European Union Maastricht treaty, which led to the formation of the European Union, saw the EEC Treaty renamed as the Treaty establishing the European Community (TEC) and renumbered. The Maastricht reforms also saw the creation of the European Union's three pillar structure, of which the European Community was the major constituent part. Following the 2005 referenda, which saw the failed attempt at launching a European Constitution, on 13 December 2007 the Lisbon treaty was signed. This saw the 'TEC' renamed as the Treaty on the Functioning of the European Union (TFEU) and, once again, renumbered. The Lisbon reforms resulted in the merging