Treaty of Rome establishing a European Economic Community, signed 1957
In the 1950s, the leaders of six European countries (France, Belgium, the Federal Republic of Germany, Italy, Luxembourg and the Netherlands) agreed to integrate their economic policies and raw material production through several treaties. The Treaty of Rome establishing a European Economic Community (known today as the Treaty establishing the European Community) merged the separate national markets of the original six European Union Member States into a single market with a range of common economic policies, including the free movement of goods, people, services and capital. The Preamble of the Treaty of Rome outlines the objectives to improve the living conditions of individuals, to promote education and to strengthen peace and liberty. In 1967, the Treaty of Rome, along with the Treaty establishing the European Coal and Steel Community (ECSC, signed 1952) and the Treaty establishing the European Atomic Energy Community (EURATOM, signed 1957), became collectively known as the “European Communities.”

Treaty on European Union, Maastricht, signed in 1992 and entered into force in 1993
The Maastricht Treaty on European Union represented a major overhaul of the European Communities and led to the creation of the European Union. The Maastricht Treaty created new levels of inter-governmental cooperation with the European Union by establishing the “Three Pillars” of the EU. Pillar One incorporates the three founding treaties mentioned above, addressing the single European market and a variety of social policies. Pillar Two addresses the EU’s Common Foreign and Security Policy. Pillar Three addresses cooperation in Justice and Home Affairs. The Maastricht Treaty affirmatively states that Member States confirm "their attachment to the principles of liberty, democracy and respect for human rights and fundamental freedoms and of the rule of law" as well as their "attachment to fundamental social rights."

Treaty of Amsterdam, signed in 1997 and entered into force in 1999
The Amsterdam Treaty amended and simplified the EC and EU treaties and added a number of protocols. The Amsterdam Treaty brings human rights to the forefront and formally recognizes the role of the Court of Justice in protecting human rights and fundamental freedoms. Article 6 as amended provides: "The Union is founded on the principles of liberty, democracy, respect for human rights and fundamental freedoms, and the rule of law, principles which are common to the Member States." The Amsterdam Treaty includes new provisions on actions to combat discrimination based on sex and a goal to "eliminate inequalities, and to promote equality, between men and women."

The Treaty of Amsterdam establishes a procedure in which the European Council may determine the existence of a "serious and persistent breach" of the foundational principles of the European Union by a member State and may then suspend certain rights of the State deriving from the Treaty on European Union. Article 6 (2) as amended by the Amsterdam Treaty reads “The Union shall respect fundamental rights, as guaranteed by the European Convention for the Protection of Human Rights and Fundamental Freedoms…and as they result from the constitutional traditions common to the Member States, as general principles of Community law.” This amendment is important because it expands the jurisdiction of the European Court of Justice to include protection of the human rights articulated in the Council of Europe's Convention on Human Rights. According to the Europa website’s Comprehensive Guide to the Amsterdam Treaty, it formally gives the European Court of Justice the “power to rule on how the Convention is being applied by the Community institutions.”

However, the Amsterdam Treaty does not commit the EU to full participant status in the ECHR (only the current EU Constitution, below, calls for EU accession to the ECHR). According to Michel Petite of the Jean Monnet Program, the Amsterdam Treaty created the anomaly “that all of the Member States are subject to the full external discipline of the Convention, while the Community is not.” At the time of the Amsterdam Treaty, according to Petite, Court of Justice judges were not willing to subordinate the Community legal order to that of the Convention, but were willing to compromise on a provision that Community law be subject to the European Convention as applied by the Court.

The Treaty of Nice, signed in 2001 and entered into force in 2003
The Treaty of Nice consolidates the EU and EC Treaties into one version. The EU Charter of Fundamental Rights was proclaimed at the European Nice summit, however, it was not incorporated into the Treaty and therefore was not made legally binding. The Treaty of Nice expanded the procedure set forth in the Amsterdam Treaty to determine breaches on foundational EU principles by creating a preventative instrument. Under the Treaty of Nice, upon the proposal of one-third of member States and the European Parliament or the European Commission, the European Council may declare that a "clear danger exists of a member State committing a serious breach of fundamental rights and address to that Member State appropriate recommendations."