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.
Czech koruna
In 1892, the Austro-Hungarian krone replaced the gulden, at the rate of one gulden equaling two kronen (which is also the reason why the 10-koruna coin is still nicknamed "pětka" or "the five" by the Czechs). The name ""krone"" was invented by the emperor, Franz Joseph I of Austria. After Austria-Hungary dissolved in 1918, the only successor state that kept the name of the currency, the koruna, was Czechoslovakia. In the late 1920s, the Czechoslovak koruna was the hardest currency in Europe. During the Second World War, the currency on the occupied Czech territory was artificially weakened. The Czechoslovak koruna was restored after the war. It underwent a highly controversial monetary reform in 1953.