The Schuman Declaration marked the true beginning of post-World War II Franco-German cooperation and the re-integration of West Germany into Western Europe. Konrad Adenauer, Chancellor of West Germany, said of the declaration, "That's our breakthrough." The ECSC was created by the Treaty of Paris (1951) and on 18 April 1951, the leaders of the six member countries (including Schuman) signed a European Declaration stating that 'the signing of this Treaty ... marked the true foundation of an organised Europe.'
The resulting ECSC introduced a common, single steel and coal market, with freely set market prices, and without import/export duties or subsidies. The success of ECSC led to further steps, foreseen by Schuman, being taken with the creation of the European Economic Community and the European Atomic Energy Community which merged in the European Communities the 1960s. The core of the proposal, the High Authority, was replaced by the European Commission and further bodies and areas of activities were created leading to the creation of the European Union in 1993.
The Declaration is viewed as one of the main founding events of the EU. In 1985, during Jacques Delors tenure as President of the European Commission, the leaders of the European Council met in Milan to decide upon 'national' symbols for the Community. They adopted those chosen by the Council of Europe previously but they changed the date of Europe Day to 9 May, in commemoration of the Schuman Declaration (the day is now also known as Schuman Day).