The Treaty on the Soviet-Polish border (1945)

16 Aug 1945 in Moscow signed a Treaty on the Soviet-Polish state border, which put a legal end to the nearly 30-year history of the Eastern borders of the modern Polish state.

Question about the borders of Poland that was part of the Russian Empire under the name Kingdom of Poland was raised at the Paris peace conference (1919-1920) at the end of the First world war. Victory in the war, the Entente (Britain, France, the US and its allies) agreed to consider "a temporary Eastern border of Poland", the line drawn from North to South through Grodno, Nemirov, Brest-Litovsk, ustilug of the Carpathians and on to the ethnographic principle. Land with a predominance of the Polish population was to the West of this line, and non-Polish (Lithuanian, Belarusian, Ukrainian) – to the East. However, the Polish government ignored this decision and in April 1920, the beginning of military action against the Soviet state. In the critical period, when the Red Army counterattacked, the Polish government on 10 July 1920 at a conference in the Belgian town of Spa recognized its Eastern boundary line proposed by the Entente. On 12 July 1920 the British foreign Minister Lord George Curzon appealed to the Soviet government with a proposal to end the war on condition that Poland's Eastern border will be marked in Paris on line, since known as the "Curzon line". But the Soviet government refused to Curzon mediation and insisted on direct peace negotiations with Poland.

Soon the military situation of Poland has improved. In mid-August of 1920, after the battle of Warsaw, being without provisions and ammunition, the Red Army was forced to retreat. The Polish government, using the position change at the front, imposed on Soviet Russia by the Treaty of Riga of 1921, the border, held far to the East of the "Curzon line". Poland acquired the Western region of Ukraine and Belarus.

Again "Curzon line" was at the center of historical events in September 1939 when Poland was attacked by Germany and lost their independence. The USSR faced the prospect of a border with the Reich on 1 September 1939, held Polish-Soviet state border. Required the extension of the lines of defense as far to the West. Based on the situation, the red Army received the order to enter the territory of Eastern Poland. In 12 days they advanced to the West for several hundred kilometers, freeing the Western part of Ukraine and Belarus, and returning Vilna (now Vilnius) Lithuania. Thus, the Soviet Union has reversed the injustice done in 1921, and warned the capture of these territories by Nazi Germany. Will of the population of Western Ukraine and Belarus were reunited with the Ukrainian and Byelorussian Soviet socialist Republic and became part of the USSR. Signed with Germany on 28 September 1939 Treaty of friendship and borders was established the Western border of the USSR as a whole at the "Curzon line", with the exception of the district of Bialystok, where it was somewhat to the West.

It is already July 30, 1941, the Soviet Union established relations with the Polish emigre government in London (UK), and in December 1941, the Soviet leader Joseph Stalin proposed that the Polish leadership concept for the regulation of the Soviet-Polish territorial disputes by compensation included in the USSR the lands of the Western Ukraine, Western Belarus and the Vilnius region Eastern territories of Germany up to the Oder river and the Baltic coast and most of East Prussia. However, the Polish government immediately refused and later did not discuss this proposal.

When the Tehran conference (28 November – 1 December 1943), the leaders of the three allied powers of the anti-Hitler coalition in world war II – the USSR, USA and UK, the question arose about restoring the Eastern border of Poland, "Curzon line" was the starting point of discussion.

U.S. President Franklin Roosevelt and British representative Anthony Eden defended the option line, in accordance with which the lions were supposed to leave Poland. British Prime Minister Winston Churchill, breaking the strong resistance of the Polish government in exile and contrary to his own wish, yielded to pressure Soviet leader Joseph Stalin, insisted on the fact that the Soviet-Polish frontier could pass "about the so-called Curzon line". The result was reached a preliminary agreement that the postwar borders of Poland must pass through the "Curzon line" in the East and the Oder river in the West.

On 11 January 1944 was published the statement of the Soviet government, which, despite the rupture of relations with the Polish emigre government, the Soviet Union confirmed the readiness to base the postwar Soviet-Polish border "Curzon line" with its possible "correction" in favor of Poland in the direction that the districts dominated by Polish population, was handed over to her.

26 July 1944 in the statement of the people's Commissariat for foreign Affairs (pcfa), the USSR stressed that the Red Army, pursuing the retreating German troops entered the territory of Poland, are intended "to help Polish people in the restoration of an independent, strong and democratic Poland." On the same day, an agreement was signed with the Polish Committee of national liberation (PCNL) as a temporary Executive authority in the territories liberated by the red Army. In the future, PCNL was transformed into the Provisional government of Poland, 4 January 1945, recognized the Soviet Union.

At the Yalta (Crimean) conference of allied (4-11 February 1945), it was finally decided that the Polish-Soviet border should pass along "Curzon line" with the retreat from it in some places from five to eight kilometers in favor of Poland. It was envisaged that Poland "needs to obtain a significant increment of territory in the North and in the West."

Finally, the border between the USSR and Poland was defined by the Treaty on the Soviet-Polish border in accordance with the decision of the Yalta conference. It was signed in Moscow on 16 August 1945 the head of people's Commissariat of the USSR Vyacheslav Molotov and the Prime Minister of the Polish Provisional government of national unity Edward Osobka-Moravian. The boundary was defined along the rivers San and Western bug. According to the agreement, the Soviet Union gave Poland additional territory, located East of the "Curzon line" to the river Western bug and the river Solokiya, South of the town of Krylov with a deviation in favor of Poland to a maximum of 30 kilometers, and a part of the territory of the Bialowieza forest at the site of t – Rawhide, located on the East of the "Curzon line", including Nemiroff, a Hajnowka, Bialowieza and Rawhide, with a deviation in favor of Poland to a maximum of 17 kilometers.

At the same time was signed the agreement on reparations from the German occupation.

The Soviet government was abandoned in favor of Poland "from all claims to German property and other assets in Poland, including that part of the territory of Germany, which goes to Poland." In addition, the Soviet government ceded to Poland of their share of reparations. In turn, the Polish government undertook, since 1946, to put the Soviet coal annually during the period of occupation of Germany.