In the fluid situation in the East following World War I, leaders of the Big Four powers of Britain, France, Italy, and the United States, meeting at Paris, decided to leave the boundary between Poland and Russia to subsequent demarcation. In December 1919, a commission headed by British Foreign Secretary Lord Curzon proposed a boundary line. Known as the Curzon Line, in the north it divided Suvalki Province between Poland and Lithuania, then extended southward toward Grodno before running west to the Bug River. It followed the Bug past the great city of Brest-Litovsk to Sokoly, then ran west around Przemysl before heading south to the Carpathians and the border of the new state of Czechoslovakia.
Neither Poland nor Russia accepted the Curzon Line. Poland won the Russo-Polish War (1919–1921) and, in the resultant Treaty of Riga of March 1921, pushed its eastern border well to the east of the Curzon Line, near to what had been the Polish-Russian frontier of 1792. Recovering territory to the Curzon Line was a major goal of post–World War I Soviet diplomacy.
In late August 1939 Germany and the Soviet Union concluded a nonaggression pact that made it possible for Germany to invade Poland, beginning World War II. The treaty also included a territorial division of Poland and the Baltic states in which the Soviet Union received much of eastern Poland. Soviet troops invaded and seized this territory in mid-September 1939, but the Germans then took it during their June 1941 invasion of the Soviet Union.
In subsequent discussions between the Soviet Union and its Western allies, Soviet leader Josef Stalin insisted that the Curzon Line be the western boundary for the Soviet Union. It was difficult for the Western powers not to agree with this, for the line had been drawn by the Western powers themselves, but such an agreement would sanction Soviet incorporation of its 1939 gains at the expense of Poland. At the Tehran Conference of November–December 1943, there was much discussion of Poland's borders. Stalin, British Prime Minister Winston Churchill, and U.S. President Franklin Roosevelt all agreed on the Oder River as the future boundary of Poland with Germany. There was, however, no agreement by the Western leaders on a tributary of the Oder, the Western Neisse River, as the southern demarcation line. Nor did the West sanction Poland taking from Germany the important port of Stettin on the west bank of the Oder. The three did agree that Poland would receive most of East Prussia, although the Soviet Union claimed the Baltic port of Königsberg (later renamed by them Kaliningrad) and land to the northeast. There was no major opposition from Western leaders to the Curzon Line as the eastern boundary of Poland, although the British did object to Soviet seizure of the predominantly Polish city of Lviv.
Stalin insisted that the Soviet Union required security against a future German attack. Obviously, a Poland that would be compensated for the loss of eastern territory to the Soviet Union by being given German territory in the west would necessarily have to look to the USSR for security, and Churchill had the difficult task of having to sell all these arrangements to the Polish government-in-exile in London. Stalin refused normal diplomatic relations with the so-called London Poles because no independent Polish government could ever concede changes that put the country at the mercy of the USSR. But a Polish government subservient to Moscow proved inevitable.
The Yalta Conference of February 1945 confirmed the decisions reached early at Tehran regarding Poland's eastern border, with but slight modification. This meant the loss to Poland of some 52,000 square miles of territory in the east. The Allies were more strenuous in objecting to the Oder-Neisse Line as its western boundary, and there was no agreement on this matter at Yalta.
Spencer C. Tucker
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