King of Poland was the emperor of Russia. After the October Revolution, Poland became an independent state and again went to war with Russia. December 8, 1919 the Supreme Council of the Entente was established Poland's eastern border, called "Curzon Line." It was held from Grodno to the Carpathians, in the 5-8 km west of the city Nemirov, Brest, Rava-Russian, Yavorov. However, Poland, taking advantage of the fact that Soviet Russia was at war against the forces of the invaders and the White Army, went to war and conquered almost the whole territory of Belarus with Minsk, Western Ukraine and much of the north-western Ukraine and Kiev. Armed to the teeth English weapon, the Polish army in 1921 and kidnapped more than 20 thousand soldiers of the Red Army. All of them were shot by the Poles.

March 18, 1921 Soviet Russia had to to sign the Treaty of Riga, in which Western Ukraine and Western Byelorussia was annexed by Poland. In these areas, pro-fascist regime of Pilsudski carried out in relation to indigenous colonial anti-national policy. Ukrainians and Belarusians, fallen under the yoke of the Polish gentry, the years have sought to connect with Ukraine and Belarus. After Nazi Germany attacked Poland, the Polish rulers, leaving their fate to his people, fled to Romania. The allies of Poland, Britain and France September 3, 1939 declared war on Germany, but for the salvation of the Polish people did not do anything. The Soviet Union has decided to correct the historical injustice done to Ukrainians and Belarusians western regions.