European Economic Community Duchesse conference centre in 1956. Together with the Ohlin Report the Spaak Report would provide the basis for the Treaty of Rome. In 1956, Paul Henri Spaak led the Intergovernmental Conference on the Common Market and Euratom at the Val Duchesse conference centre, which prepared for the Treaty of Rome in 1957. The conference led to the signature, on 25 March 1957, of the Treaty of Rome establishing a European Economic Community. The resulting communities were the European Economic Community (EEC) and the European Atomic Energy Community (EURATOM or sometimes EAEC). These were markedly less supranational than the previous communities,
European Economic Community the ECSC and Euratom were merged with that of the EEC, creating a single institutional structure governing the three separate Communities. From here on, the term "European Communities" were used for the institutions (for example, from "Commission of the European Economic Community" to the "Commission of the European Communities"). The Council of the European Communities was a body holding legislative and executive powers and was thus the main decision making body of the Community. Its Presidency rotated between the member states every six months and it is related to the European Council, which was an informal gathering of national leaders