"i."Joseph Stalin at the 1943 Tehran Conference discussed with Winston Churchill and Franklin D. Roosevelt new post-war borders in central-eastern Europe, including the shape of a future Poland. He endorsed the Piast Concept, which justified a massive shift of Poland's frontiers to the west. Stalin resolved to secure and stabilize the western reaches of the Soviet Union and disable the future military potential of Germany by constructing a compact and ethnically defined Poland (along with the Soviet ethnic Ukraine, Belarus and Lithuania) and by radically altering the region's system of national borders. After 1945, the Polish communist regime wholeheartedly adopted and promoted the Piast Concept, making it the centerpiece of their claim to be the true inheritors of Polish nationalism. After all the killings and population transfers during and after the war, the country was 99% "Polish".