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.
Zaolzie
Poland signed a treaty with Czechoslovakia in Warsaw on 13 June 1958 confirming the border as it existed on 1 January 1938. After the Communist takeover of power, the industrial boom continued and many immigrants arrived in the area (mostly from other parts of Czechoslovakia, mainly from Slovakia). The arrival of Slovaks significantly changed the ethnic structure of the area, as almost all the Slovak immigrants assimilated into the Czech majority in the course of time. The number of self-declared Slovaks is rapidly declining. The last Slovak elementary school was closed in Karviná several years ago. Since the dissolution of Czechoslovakia in 1993, Zaolzie has been part of the independent Czech Republic. However a significant Polish minority still remains there.