ABSTRACT
European integration is characterized by increasing institutionalization and a gradual enlargement of member states. In 1951, the European Coal and Steel Community was established by six members. Within a few years, these members decided to integrate other sectors of their economies. In 1957 they signed the Treaties of Rome, creating the European Atomic Energy Community and the European Economic Community with the goals of removing trade barriers and forming a common market. Additional sectors were gradually included, such as a customs union, a monetary union, and a common currency for a subset of EU countries. With the Treaty of Maastricht in 1993, the EU extended its sphere of infl uence to the fi elds of foreign and domestic policy and to the security sector.
