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).
European Economic Community In place of the ECSC's Council of Ministers was the Council of the European Economic Community, and in place of the High Authority was the Commission of the European Communities. There was greater difference between these than name: the French government of the day had grown suspicious of the supranational power of the High Authority and sought to curb its powers in favour of the intergovernmental style Council. Hence the Council had a greater executive role in the running of the EEC than was the situation in the ECSC. By virtue of the Merger Treaty in 1967, the executives of