This report provides a comprehensive analysis of the Treaty on European Union (Maastricht Treaty) of 1991, detailing its historical and political context and impact on the European Union. The report begins with an introduction to the EU, defining it as an economic and political partnership among its member states, and outlining the role of treaties in its development. It then explores the Maastricht Treaty itself, explaining its key elements, objectives, and the concept of European citizenship. The report further examines the historical and political development of the EU, highlighting the evolution from the post-World War II era to the signing of the Maastricht Treaty. It also discusses Article 1 of the TEU, which outlines the common provisions and principles of the EU and its constitutional structure, including the three-pillar structure. The report concludes by emphasizing the enhancement of European integration facilitated by the EU and the distinct issues addressed within European law.