The treaty that created the European Union from the European Communities and entered into force in 1993 was the Maastricht Treaty.
Signed in Maastricht, Netherlands, in 1992, the Treaty on European Union established a broader political framework around existing European Communities. It introduced cooperation in areas including foreign and security policy and justice and home affairs.
The treaty also set convergence requirements for countries seeking to adopt the single currency. These included criteria concerning inflation, public finances, exchange-rate stability and interest rates, although the euro was introduced later in stages.
The Maastricht Treaty did not immediately give every European country the euro or create a fully federal state. Later treaties, including Amsterdam, Nice and Lisbon, amended the Union’s institutions and rules.