Central and Eastern Europe Soviet Union; the independent states in former Yugoslavia (which were not considered part of the Eastern bloc); and the three Baltic states – Estonia, Latvia, Lithuania (which chose not to join the CIS with the other 12 former republics of the USSR). The CEE countries are further subdivided by their accession status to the European Union (EU): the eight first-wave accession countries that joined the EU on 1 May 2004 (Estonia, Latvia, Lithuania, Czech Republic, Slovakia, Poland, Hungary, and Slovenia), the two second-wave accession countries that joined on 1 January 2007 (Romania and Bulgaria) and the third-wave accession country that
Treaty on European Union Treaty on European Union The Treaty on European Union (2007) is one of the primary Treaties of the European Union, alongside the Treaty on the Functioning of the European Union (TFEU). The TEU forms the basis of EU law, by setting out general principles of the EU's purpose, the governance of its central institutions (such as the Commission, Parliament, and Council), as well as the rules on external, foreign and security policy. While the current version of the TEU entered into force in 2009, following the Treaty of Lisbon (2007), the older form of the same document was implemented by