European integration for greater transparency and trust among themselves. This transfer of national powers to a "Community" to be exercised by its Commission was paralleled under the 1957 Treaty of Rome establishing the European Atomic Energy Community (or Euratom) and the European Economic Community (EEC) in Brussels. In 1967, the Merger Treaty (or Brussels Treaty) combine 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. In 1987, the Single European Act (SEA) was the first major revision of the Treaty of Rome that
European Coal and Steel Community their fields rapidly expanded and the EEC became the most important tool for political unification, overshadowing the ECSC. Despite being separate legal entities, the ECSC, EEC and Euratom initially shared the Common Assembly and the European Court of Justice, although the Councils and the High Authority/Commissions remained separate. To avoid duplication, the Merger Treaty merged these separate bodies of the ECSC and Euratom with the EEC. The EEC later became one of the three pillars of the present day European Union. The Treaty of Paris was frequently amended as the EC and EU evolved and expanded. With the treaty due