Dissolution of Czechoslovakia
Since the federalization in 1968, Czechoslovakia had divided citizenship, either of the Czech Socialist Republic or of the Slovak Socialist Republic (the word 'Socialist' was dropped from both names shortly after the Velvet Revolution). This distinction, however, had little effect on the citizen's life. On January 1, 1993, all Czechoslovak citizens automatically became citizens either of the Czech Republic or the Slovak Republic, based on their previous citizenship, permanent residence address, birthplace, family ties, job, and other criteria. Additionally, people had one year's time to claim the other citizenship under certain conditions.
Hungary–Slovakia relations
After the first break-up of Czechoslovakia in March 1939, Hungary was the first state which officially recognized the independent Slovakia. Subsequently, Hungary and Slovakia established embassies in Bratislava and Budapest and kept diplomatic relations during the World War Two. Despite a formal alliance inside the Berlin pact (1940) and a common war against the Anti-Hitler coalition, Slovak-Hungarian political relations maintained on the brink of war due to the frontier dispute and the oppression of Slovak minority in Hungary and Hungarian minority in Slovakia. The restoration of Czechoslovakia and the liquidation of the independent Slovakia in 1945 led to the end of the first period of Hungary-Slovakia's relations.