On 1 December 1993 the Treaty on European Union, commonly called the Maastricht Treaty, entered into force and formally created the European Union (EU). Negotiated by the then-12 member states of the European Community and signed in February 1992, the treaty marked a major institutional and political shift: it preserved the existing European Communities while adding new common policies and structures aimed at deeper integration. Key provisions and structure - Three-pillar structure: The treaty established a framework often described as three pillars. The first pillar comprised the European Communities (economic, social and environmental policies governed largely by supranational institutions). The second pillar covered a Common Foreign and Security Policy (CFSP) based on intergovernmental cooperation. The third pillar created cooperation on Justice and Home Affairs (JHA), also intergovernmental in nature. This architecture aimed to balance supranational decision-making with areas where states retained primary control. - Citizenship and rights: Maastricht introduced the notion of EU citizenship, granting nationals of member states rights such as the right to move and reside freely within member states and the right to vote and stand in local and European Parliament elections in their country of residence. - Economic and Monetary Union (EMU): The treaty set out a staged process toward EMU, including convergence criteria (on inflation, public finances, exchange rate stability and interest rates) that member states would need to meet to adopt a single currency. It also created the institutional groundwork that would later enable the launch of the euro. - Institutional changes: Maastricht expanded the powers of the European Parliament and strengthened the role of the European Commission and the European Court of Justice in certain policy areas. It also introduced the co-decision procedure (later renamed the ordinary legislative procedure), enhancing the Parliament’s legislative role alongside the Council. Political context and significance The Maastricht Treaty reflected a post-Cold War momentum for deeper European integration and a desire among member states to coordinate policy across a broader range of areas. Supporters argued the treaty modernized European institutions and prepared the continent for the economic and political challenges of the 1990s and beyond. Critics in several countries feared a loss of national sovereignty; ratification narrowly passed in some states and was rejected in others, prompting subsequent adjustments and clarifications. Implementation and legacy Although the treaty created the EU as a legal and political entity on 1 December 1993, many of its longer-term aims unfolded over subsequent years: the single currency (the euro) launched in non-physical form in 1999 and as notes and coins in 2002; CFSP and Justice and Home Affairs evolved through further treaties and policy practice; and the EU’s institutional architecture continued to be reformed by later treaties (notably Amsterdam, Nice and Lisbon). The Maastricht Treaty remains a foundational milestone in the EU’s constitutional development, marking the transition from a primarily economic community to a political union with broader ambitions. Notes on interpretation Descriptions of Maastricht’s effects and the balance between supranational and intergovernmental elements are subject to scholarly and political debate. This account summarizes widely documented provisions and broadly accepted historical consequences without attributing contested contemporary opinions to specific individuals.