What Day Was the Maastricht Treaty entering into force (EU founded)?

About this date

The Maastricht Treaty entered into force, formally establishing the European Union and creating the framework for a common EU citizenship, foreign and security policy cooperation, and the eventual introduction of the euro currency.

The treaty had been signed by member states the previous year and required ratification processes, including a closely watched Danish referendum, before taking effect.

The treaty's ratification faced a genuine setback when Danish voters initially rejected it in a June 1992 referendum, requiring negotiated opt-out concessions before a second Danish vote approved it later that year.

The treaty also established the "three pillars" structure of EU governance, dividing cooperation into separate legal frameworks for economic policy, foreign and security policy, and justice matters, a structure later simplified by subsequent treaties.