Dissolution of Czechoslovakia
The Dissolution of Czechoslovakia (, ), which took effect on 1 January 1993, was an event that saw the self-determined split of the federal state of Czechoslovakia into the Czech Republic and Slovakia, entities that had arisen before as the "Czech Socialist Republic" and the "Slovak Socialist Republic" in 1969 within the framework of a federal republic.
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.