Treaty of Rome in the context of "Single market"

The European Union (EU) has expanded a number of times throughout its history by way of the accession of new member states to the Union. To join the EU, a state needs to fulfil economic and political conditions called the Copenhagen criteria (named after the Copenhagen summit in June 1993), which require a stable democratic government that respects the rule of law, and its corresponding freedoms and institutions. According to the Maastricht Treaty, each current member state and the European Parliament must agree to any enlargement. The process of enlargement is sometimes referred to as European integration. This term is also used to refer to the intensification of co-operation between EU member states as national governments allow for the gradual harmonisation of national laws.

The EU's predecessor, the European Economic Community, was founded with the Inner Six member states in 1958, when the Treaty of Rome came into force. Since then, the EU's membership has grown to twenty-seven, with the latest member state being Croatia, which joined in July 2013. The most recent territorial enlargement of the EU was the incorporation of Mayotte in 2014. Campione d'Italia joined the EU Customs Union in 2020. The most notable territorial reductions of the EU, and its predecessors, have been the exit of Algeria upon independence in 1962, the exit of Greenland in 1985, and the withdrawal of the United Kingdom in 2020.

The Treaty of Lisbon (initially known as the Reform Treaty) is a European agreement that amends the two treaties which form the constitutional basis of the European Union (EU). The Treaty of Lisbon, which was signed by all EU member states on 13 December 2007, entered into force on 1 December 2009. It amends the Maastricht Treaty (1992), known in updated form as the Treaty on European Union (2007) or TEU, as well as the Treaty of Rome (1957), known in updated form as the Treaty on the Functioning of the European Union (2007) or TFEU. It also amends the attached treaty protocols as well as the Treaty establishing the European Atomic Energy Community (EURATOM).

Prominent changes included the move from unanimity to qualified majority voting in at least 45 policy areas in the Council of Ministers, a change in calculating such a majority to a new double majority, a more powerful European Parliament forming a bicameral legislature alongside the Council of Ministers under the ordinary legislative procedure, a consolidated legal personality for the EU and the creation of a long-term president of the European Council and a High Representative of the Union for Foreign Affairs and Security Policy. The Treaty also made the Union's bill of rights, the Charter of Fundamental Rights, legally binding. For the first time, the treaty gave member states the explicit legal right to leave the EU, and established a procedure by which to do so.

The European Economic Community (EEC) was a regional organisation created by the Treaty of Rome of 1957, aiming to foster economic integration among its member states. It was subsequently renamed the European Community (EC) upon becoming integrated into the first pillar of the newly formed European Union (EU) in 1993. In the popular language, the singular European Community was sometimes inaccurately used in the wider sense of the plural European Communities, in spite of the latter designation covering all the three constituent entities of the first pillar. The EEC was also known as the European Common Market (ECM) in the English-speaking countries, and sometimes referred to as the European Community even before it was officially renamed as such in 1993. In 2009, the EC formally ceased to exist and its institutions were directly absorbed by the EU. This made the Union the formal successor institution of the Community.

The Community's initial aim was to bring about economic integration, including a common market and customs union, among its six founding members: Belgium, France, Italy, Luxembourg, the Netherlands and West Germany. It gained a common set of institutions along with the European Coal and Steel Community (ECSC) and the European Atomic Energy Community (EURATOM) as one of the European Communities under the 1965 Merger Treaty (Treaty of Brussels). In 1993, a complete single market was achieved, known as the internal market, which allowed for the free movement of goods, capital, services, and people within the EEC. In 1994 the internal market was formalised by the EEA agreement. This agreement also extended the internal market to include most of the member states of the European Free Trade Association, forming the European Economic Area, which encompasses 15 countries.

The Treaty on the Functioning of the European Union (TFEU) is one of two treaties forming the constitutional basis of the European Union (EU), the other being the Treaty on European Union (TEU). It was previously known as the Treaty Establishing the European Community (TEC).

The Treaty originated as the Treaty of Rome (fully the Treaty establishing the European Economic Community), which brought about the creation of the European Economic Community (EEC), the best-known of the European Communities (EC). It was signed on 25 March 1957 by Belgium, France, Italy, Luxembourg, the Netherlands and West Germany and came into force on 1 January 1958. It remains one of the two most important treaties in the modern-day European Union (EU).

A European Union Association Agreement or simply Association Agreement (AA) is a treaty between the European Union (EU, or its predecessors), its Member States and a non-EU country or bloc of countries that governs bilateral relations. Areas frequently covered by such agreements include the development of political, trade, social, cultural and security links. The provision for an association agreement was included in the Treaty of Rome, which established the European Economic Community, as a means to enable co-operation of the Community with the United Kingdom, which had retreated from the treaty negotiations at the Messina Conference of 1955. According to the European External Action Service, for an agreement to be classified as an AA, it must meet several criteria:

The EU typically concludes Association Agreements in exchange for commitments to political, economic, trade, or human rights reform in a country. In exchange, the country may be offered tariff-free access to some or all EU markets (industrial goods, agricultural products, etc.), and financial or technical assistance. Most recently signed AAs also include a Free Trade Agreement (FTA) between the EU and the external party.

The Euratom Treaty, officially the Treaty establishing the European Atomic Energy Community, established the European Atomic Energy Community. It was signed on 25 March 1957 at the same time as the Treaty establishing the European Economic Community (EEC Treaty).

The Euratom Treaty is less well known because of the lower profile of the organisation that it founded. The EEC has evolved into what is now the European Union, but Euratom has remained much the same as it was in 1957 although it is governed by the institutions of the European Union. It was established with its own Commission and Council, but the 1967 Merger Treaty merged these institutions of Euratom and the European Coal and Steel Community with those of the EEC.