The Iron & Steel Community - the precursor to the EU - statred in 1951 with the Treaty of Paris and had been under discusion since 1950
The aim was to "make war not only unthinkable but materially impossible" which was to be achieved by regional integration, of which the ECSC was the first step. The Treaty would create a common market for coal & steel among its member states which served to neutralise competition between European nations over natural resources, particularly in the Ruhr.
IIRC Churchill approved but said it was not for us - we after all had the Empire & Commonwealth............
I've never really liked the EU set up - but it survives and prospers in spite of everything - and we continually misunderstand the commitment of other people to it. The British always saw it as a Common Market whereas Europeans saw it as something much bigger. Amazing that both sides can still misread the runes after all this time...............