The Merger Treaty
The idea of rationalizing the institutional structure of the three Communities was first introduced by the Convention on Certain Institutions Common to the European Communities of 25 March 1957.
The Convention provided for the establishment of a single Assembly (the EP), a single Court of Justice, and a single Economic and Social Committee for all three Communities. Further rationalization took place in April 1965 when the Treaty (known as the Merger Treaty) establishing a Single Council and a Single Commission of the European Communities was signed.
The Treaty came into force on 13 July 1967. Under the Merger Treaty the three Communities shared the same institutions, although they remained legally independent and the competencies of the institutions were subject to the respective Treaties.
