Slovakia
The Slovak Republic and the Czech Republic went their separate ways after 1 January 1993, an event sometimes called the Velvet Divorce. Slovakia has remained a close partner with the Czech Republic. Both countries co-operate with Hungary and Poland in the Visegrád Group. Slovakia became a member of NATO on 29 March 2004 and of the European Union on 1 May 2004. On 1 January 2009, Slovakia adopted the Euro as its national currency.
Origins of Czechoslovakia
Both Czechs and Slovaks struggled against a powerful neighbouring people; Germans in the case of the Czechs, Hungarians in the case of the Slovaks (see History of the Czech Republic and History of Slovakia). Contacts between the Czechs and Slovaks arose in the late fourteenth century, when Slovaks started to study at the University of Prague; in the fifteenth century, with the campaigns of the Czech Hussite armies to Slovakia; and in the seventeenth century, when Czech Protestants fled to Slovakia. Between the fifteenth and eighteenth centuries, some educated Slovaks used written Czech as well as Slovak and Latin (see History of the Slovak language). The Czechs and Slovaks were also formally united in 1436–1439, 1453–1457, and 1490–1918, when Hungary (which included Slovakia), Bohemia and other Central European states were ruled by the same kings.