1958
On June 13, 1958, the Agreement concerning the final demarcation of the state frontier between Czechoslovakia and Poland was signed in Warsaw. Adam Rapacki signed for Poland and Václav David signed for Czechoslovakia. The treaty confirmed the border at the line of January 1, 1938, the situation before the Nazi-imposed Munich Agreement transferred territory from Czechoslovakia to Poland.
Read more about this topic: Territorial Evolution Of Poland