The Intergovernmental Conference on the Common Market and Euratom at Val Duchesse in 1956 drew up the essentials of the new treaties. Euratom would foster co-operation in the nuclear field, at the time a very popular area, and would, along with the EEC, share the Common Assembly and Court of Justice of the ECSC, but not its executives. Euratom would have its own Commission, with fewer powers than the ECSC's High Authority, and Council. On 25 March 1957, the Treaties of Rome were signed by the ECSC members and on 1 January 1958 they came into force.
To save on resources, these separate executives created by the Rome Treaties were merged in 1965 by the Merger Treaty. The institutions of the EEC would take over responsibilities for the running of the EEC and Euratom, with all three then becoming known as the European Communities although each legally existed separately. In 1993, the Maastricht Treaty created the European Union, which absorbed the Communities into the European Community pillar, yet Euratom still maintains a distinct legal personality and the treaty remains in force relatively un-amended from its original signing.
The European Constitution was intended to consolidate all previous treaties and increase democratic accountability in them. The Euratom had not been amended in the same way the other treaties had and hence the European Parliament had been granted few powers of it. However, the reason it had gone unamended was the same reason the Constitution left it to remain separate from the rest of the EU: anti-nuclear sentiment among the European electorate which may unnecessarily turn voters against the treaty.