The Treaty of Accession 2003 changed a number of points which were originally laid down in the Treaty of Nice and entered into force on 1 May 2004, the day of the Enlargement of the European Union in 2004.
The official title thereof is Treaty between the Kingdom of Belgium, the Kingdom of Denmark, the Federal Republic of Germany, the Hellenic Republic, the Kingdom of Spain, the French Republic, Ireland, the Italian Republic, the Grand Duchy of Luxembourg, the Kingdom of the Netherlands, the Republic of Austria, the Portuguese Republic, the Republic of Finland, the Kingdom of Sweden, the United Kingdom of Great Britain and Northern Ireland (Member States of the European Union) and the Czech Republic, the Republic of Estonia, the Republic of Cyprus, the Republic of Latvia, the Republic of Lithuania, the Republic of Hungary, the Republic of Malta, the Republic of Poland, the Republic of Slovenia, the Slovak Republic, concerning the accession of the Czech Republic, the Republic of Estonia, the Republic of Cyprus, the Republic of Latvia, the Republic of Lithuania, the Republic of Hungary, the Republic of Malta, the Republic of Poland, the Republic of Slovenia and the Slovak Republic to the European Union.
The European Union comprises a large number of overlapping legal structures which is a result of it being defined by successive international treaties:
The Treaty of Accesision 2003 changes
as well as other acts which together form the current legal framework (acquis) of the EU.
Changes include the way the Qualified Majority Voting is handled in the Council of the European Union.
See also: European Union Law