I hope one of these helps somehow if not I am sorry
In 1795, Poland's territory was completely partitioned among the Kingdom of Prussia, the Russian Empire, and Austria. Poland regained its independence as the Second Polish Republic in 1918 after World War I, but lost it in World War II through occupation by Nazi Germany and the Soviet Union
The borders are shifted to the east relative to present-day Poland, including parts of what is now Lithuania, Ukraine, and Belarus. This territory that was part of Poland between the World Wars, but is excluded from today's Poland, is known as the Kresy
After the end of World War II Europe was divided between communist and non-communist controlled territory. Germany and its former capital Berlin was divided into French, American, British and Soviet sectors. Latvia, Estonia, and Lithuania became republics within the Soviet Union
On September 29, 1939, Germany and the Soviet Union agree to divide control of occupied Poland roughly along the Bug River—the Germans taking everything west, the Soviets taking everything east.
This is called the Curzon line.