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
Three pillars of the European Union Three pillars of the European Union Between 1993 and 2009, the European Union (EU) legally comprised three pillars. This structure was introduced with the Treaty of Maastricht on 1 November 1993, and was eventually abandoned on 1 December 2009 upon the entry into force of the Treaty of Lisbon, when the EU obtained a consolidated legal personality. Within each pillar, a different balance was struck between the supranational and intergovernmental principles. Supranationalism was strongest in the first pillar. Its function generally corresponded at first to the three European Communities (European Coal and Steel Community (ECSC), European Economic Community (EEC) and