Second Polish Republic

Second Polish Republic was name of Polish state from 1918 (end of WWI) through 1939 (start of WWII). When its borders were fixed in 1922 after several wars, it had borders with Czechoslovakia, Weimar Republic (Germany), Free City of Danzig, Latvia, Lithuania, Romania and Soviet Union. Józef Piłsudski was the leader during most of the state's existence.
Successors.
The Second Polish Republic, in 1939, was invaded by the Greater German Reich and the U.S.S.R. after refusing to make territorial changes towards Germany. Poland was then fully occupied by both countries 39 days later. It continued it's existence as the Polish Underground State until 1945 when Poland was released but made a communist, soviet, satellite state.