Soviet territorial annexations during World War II were later ratified by the Allies at the Tehran Conference , the Yalta Conference and at the Potsdam Conference . When the Soviet Union broke up , the several parts of Kresy remained within the former Soviet republics as they gained their own independence . Even though the Eastern Borderlands are no longer in Poland , the provinces are still home to Polish minorities and the memory of " Kresy " , as a continuation of their centuries long nationhood , is maintained among many of them . However , in present day Poland the attachment to the " mythic Kresy " , including the prewar vision of the regions as a peaceful , idyllic , rural land , has been debunked in Polish political discourse after the collapse of the Soviet Union
Yalta Conference
Yalta Conference
Kresy