The Curzon Line and territorial changes to Poland, 1945
At the end of World War I the Allies agreed that an independent Polish state should be formed from territories previously part of the Russian Empire, the Austro-Hungarian Empire and Germany. The Treaty of Versailles in 1919 said that the eastern border of Poland would be "subsequently determined." The lands lying between Poland and its eastern neighbours were inhabited by a mixed population of Poles, Russian speaking Jews, Lithuanians, Jiddish speaking Jews, Ukrainians and White Russians, with no single group being a majority. The Allies suggested a line running from Grodno through Brest-Litovsk to Lwow, although leaving unclear which side of the proposed border Lwow would be on.
Because the Russian Empire had collapsed into a state of civil war following the Russian Revolution, there was no recognised Russian government with whom the eastern border of Poland could be negotiated. However, one of the first acts of the Lenin government was to publicly denounce the treaties of partitions of Poland. That left Poland in legal possesion of the country that Poland had held before the Partitions of Poland in 1772. The Bolshevik regime in Russia, on the other hand, wanted to invade Poland in order to carry the socialist revolution into the heart of Europe, and particularly into Germany. In this circumstances war was inevitable, and broke out in late 1919.
In December 1919, the Allied powers made the following declaration: "The Principal Allied and Associated Powers, recognising that it is important as soon as possible to put a stop to the existing conditions of political uncertainty in which the Polish nation is placed, and without prejudging the provisions, which must in the future define the eastern frontiers of Poland, hereby declare that they recognize the right of the Polish Government to proceed, according to the conditions previously provided by the Treaty with Poland of June 28, 1919, to organise a regular administration of the territories of the former Russian Empire situated to the West of the line described below. The rights that Poland may be able to establish over the territories situated to the East of the said line are expressly reserved."
After an initial Polish offensive into Ukraine, which captured Kiev in May 1920, the Bolsheviks gained the advantage and advanced into Poland, and in July the Poles appealed to the Allies to intervene. On 11 July Lord Curzon proposed to the Soviet government a ceasefire along the line which had been suggested the previous year. The Soviets, believing they had the upper hand, rejected the proposal, and fighting continued. In August, however, the Soviets were defeated just outside Warsaw and forced to retreat. At the Treaty of Riga in March 1921 the Soviets had to concede a frontier well to the east of the Curzon Line, giving Poland both Lwow and Wilno (today Vilnius}. The area around Wilno, called Central Lithuania was subject of referendum in 1922, that was followed by incorporation to Poland according to wish of 65% of voters. The Polish-Soviet border was recognised by the League of Nations in 1923 and confirmed by various Polish-Soviet agreements.
The terms of the Molotov-Ribbentrop Pact of August 1939 provided for the partition of Poland along the line of the San, Vistula and Narew rivers. In September, after the military defeat of Poland, the Soviet Union annexed all territories east of the Curzon Line plus Bialystok and Eastern Galicia. The territories east of this line were incorporated into the Byelorussian and Ukrainian Soviet Socialist Republics after forged referendum, and hundreds of thousands of Poles and a lesser number of Jews were deported eastwards into the Soviet Union. In July 1941 these territories were seized by Germany in the course of Hitler's invasion of the Soviet Union. During the German occupation most of the Jewish population was killed.
In 1944 the Soviet armed forces recaptured eastern Poland from the Germans. The Soviets unilaterally declared the former Soviet-German border (approximately the Curzon Line) to be the new frontier between the Soviet Union and Poland. This time, however, Bialystok was retained by Poland. The Polish government-in-exile in London bitterly opposed this action, and at the Teheran and Yalta conferences between Stalin and the western Allies, Roosevelt and Churchill asked Stalin to reconsider, particularly over Lwow, but he refused. The Curzon Line thus became the permanent eastern border of Poland, and was recognised as such by the western Allies in July 1945.
The territory which lay between the Curzon Line and the 1921 eastern border of Poland had a population of about 12 million people on the area of 188 000 km2. According to statistics from the Polish census of 1931 (which was unlikely to underestimate the number of Poles), the population of these territories by mother-tongue was:
The elimination of the Jewish population between 1941 and 1945 probably left Ukrainians and Byelorussians as a majority of the population in the territories, though far from a large one. The cities of Lwow, Wilno, Grodno and some smaller towns had Polish majorities during this period.History of the Curzon Line
Ethnography of Eastern Poland
Poles 4,794,000 39.9%
Ukrainians and Ruthenians 4,139,000 34.4%
Jews 1,045,000 08.4%
Byelorussians 993,000 08.5%
Russians 120,000 01.0%
Lithuanians 76,000 00.6%
Others and not given 845,000 06.4% (mainly Poleszuks from Polesie)
By religion the population was classified as follows:Roman Catholics 4,016,000 33.4%
Greek Catholics or Uniates 3,050,000 25.4%
Orthodox 3,529,000 29.3%
Other Christians: 180,000 01.5%
Hebrew 1,222,000 10.2%
It will be seen from these figures that although the Poles were the largest single ethnic and religious group in these territories, they were far from being a majority, and that the Ukrainians, Byelorussians and Russians together outnumbered them. If there had been a plebiscite in the area (which neither side would have permitted), the attitude of the Jewish population would have determined the outcome.