Which treaty established the European Union?

The Maastricht Treaty, signed in 1992 and effective from November 1, 1993, formally established the European Union (EU). This landmark agreement introduced the concept of European citizenship, laid the groundwork for the single European currency (the Euro), and created a common foreign and security policy, fundamentally transforming the existing European Communities into a more integrated political and economic union.

• The Treaty of Rome (1957) established the European Economic Community (EEC), a precursor focused on economic integration, not the EU itself.
• The Treaty of Lisbon (2007) amended existing treaties to streamline EU institutions and decision-making processes, but it did not establish the Union.
• The Schengen Agreement (1985) created a borderless travel area within Europe, which is a separate but related aspect of European cooperation, not the founding treaty of the EU.