• Germany, France, Italy, the Netherlands, Belgium, and Luxembourg sign the Coal and Steel treaty to manage heavy industries together.
  • Coal and Steel Treaty members sign the Treaty of Rome, which leads to the creation of a “common market” under the European Economic Community (EEC).
  • The Brussels Treaty merges leadership positions within the three separate organizations into one large body known as the Council of Ministers.
  • The first enlargement of the EC took place with the addition of Denmark, Ireland, and the United Kingdom.
  • The European Council is established to specifically set long-term agendas for political and economic integration.
  • Europeans elect European Parliament members for the first time.
  • Single European Act (SEA) comes into enforcement, expanding common market flexibility.
  • The Maastricht Treaty is signed, which established rules of common currency in addition to providing further coordination for foreign and security policy. The European Community formally changes its name to the European Union.
  • A new currency, the euro, was launched in world money markets. It became the unit of exchange for all of the EU states except the United Kingdom, Sweden, and Denmark.
  • Treaty of Nice entered into force to set forth rules streamlining the size and procedures of EU institutions.
  • Ten new countries joined the EU, and the European constitution is signed by all 25 EU countries. Ratification failed in 2005.
  • Bulgaria and Romania join the EU, bringing membership to 27 countries.
  • Treaty of Lisbon entered into force to provide EU with modern institutions to address issues such as globalization, climate change, security, and energy.
  • At a European Council meeting in Brussels, EU leaders adopt a 10-year strategy for smart, sustainable and inclusive growth: Europe 2020. They also decide to open accession negotiations with Iceland.
  • Croatia becomes the 28th country to join the European Union.
  • The European Union enforces economic sanctions against Russia in response to Russia's "illegal annexation of Crimea and deliberate destabilization of a neighboring sovereign country".
  • The United Kingdom votes in favor of the referendum to leave the European Union in 2019, which is commonly known as Brexit.
  • The United Kingdom officially leaves the European Union, initiating an 11-month transition period while trade negotiations are finalized.


Ellicott, Karen. "European Union." Countries of the World and Their Leaders Yearbook 2007. Farmington Hills, MI: Thomson Gale, 2006. 2077-082.

Official European Union Website: The History of the European Union