European Union By Aarontaylor Period: 1939 to 2021 EU 1945 End Of Word War II 1957 Treaty of Paris 1979 First direct elections to parliment 1981 Single European Act 1993 Copenhagen criteria defined 1999 Official use of the Euro 2005 France and netherlands reject the EU constitution 2009 Libson Treaty 2013 Accession of Croatia 2017 Start of BREXIT