It was established with its own Commission and Council, but the 1967 Merger Treaty merged these institutions of Euratom and the European Coal and Steel Community with those of the EEC.

The Euratom treaty has seen very little amendment because of later sensitivity surrounding nuclear power in European public opinion.

Since the end of World War II, sovereign European countries have entered into treaties and thereby co-operated and harmonised policies (or pooled sovereignty) in an increasing number of areas, in the European integration project or the construction of Europe (French: la construction européenne).

The following timeline outlines the legal inception of the European Union (EU)—the principal framework for this unification.

The EU inherited many of its present responsibilities from the European Communities (EC), which were founded in the 1950s in the spirit of the Schuman Declaration.