Brussels and the European Union a provisional seat, though with the Common Assembly in Strasbourg as that was the only city with a large enough hemicycle (the one used by the Council of Europe). This agreement was temporary, and plans were set to relocate the institutions to Saarbrücken which would serve as a "European District", but this did not occur. The 1957 Treaties of Rome established two new communities, the European Economic Community (EEC) and the European Atomic Energy Community (Euratom). These shared the Assembly and Court of the ECSC but created two new sets of Councils and Commissions (equivalent to the ECSC's High Authority).
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