EU Treaties Cheat Sheet: From Rome to Lisbon

The EU Knowledge section of the EPSO exam frequently tests your understanding of the major treaties. Here's a chronological summary of each treaty and its key contributions.

Treaty of Rome (1957)

Founded the European Economic Community (EEC) and EURATOM. Established the common market, free movement of goods, and the customs union. Signed by Belgium, France, Germany, Italy, Luxembourg, and the Netherlands (the original six).

Merger Treaty (1965)

Merged the executive bodies of the three European Communities (ECSC, EEC, EURATOM) into a single Commission and Council. Simplified institutional structure.

Single European Act (1986)

First major revision of the Treaty of Rome. Set the deadline for completing the Single Market by December 31, 1992. Introduced qualified majority voting in the Council for Single Market measures. Formally established European Political Cooperation (foreign policy).

Maastricht Treaty (1992)

Created the European Union with its three-pillar structure:

• Pillar 1: European Communities (supranational)
• Pillar 2: Common Foreign and Security Policy (CFSP, intergovernmental)
• Pillar 3: Justice and Home Affairs (intergovernmental)

Introduced EU citizenship, the roadmap to the Euro, and the co-decision procedure (giving the European Parliament real legislative power).

Treaty of Amsterdam (1997)

Incorporated the Schengen Agreement into EU law. Strengthened the Common Foreign and Security Policy. Moved asylum, immigration, and civil judicial cooperation from Pillar 3 to Pillar 1 (making them supranational). Extended co-decision to more policy areas.

Treaty of Nice (2001)

Prepared the EU for enlargement (the 2004 "big bang" of 10 new members). Reformed voting weights in the Council and the composition of the Commission. Extended qualified majority voting to more areas. Proclaimed the Charter of Fundamental Rights (not yet legally binding).

Treaty of Lisbon (2007)

The current foundational treaty. Key changes:

• Abolished the pillar structure, merged everything into a single legal framework
• Created the permanent President of the European Council
• Created the High Representative for Foreign Affairs and Security Policy
• Made the Charter of Fundamental Rights legally binding
• Gave national parliaments a role in EU legislation (subsidiarity check)
• Introduced the citizens' initiative (1 million signatures can invite the Commission to propose legislation)
• Extended qualified majority voting (QMV) and the ordinary legislative procedure to more policy areas
• Introduced Article 50 (voluntary withdrawal clause)

Key Exam Tips

EPSO questions often test:

• Which treaty introduced a specific institution or mechanism
• The chronological order of treaties
• What each treaty changed relative to its predecessor
• The difference between the treaties (TEU vs TFEU after Lisbon)

Focus on the "firsts": which treaty first introduced QMV, co-decision, EU citizenship, the Euro roadmap, Article 50, etc.