"Europe Day held on 9 May every year celebrates peace and unity in Europe. The date marks the anniversary of the historic 'Schuman declaration'.

At a speech in Paris in 1950, Robert Schuman, the then French foreign minister, set out his idea for a new form of political cooperation in Europe, which would make war between Europe's nations unthinkable.

His vision was to create a European institution that would pool and manage coal and steel production. A treaty creating such a body was signed just under a year later. Schuman's proposal is considered to be the beginning of what is now the European Union."

https://europa.eu/european-union/about-eu/symbols/europe-day_en