Poles in the Soviet Union
The Polish minority in the Soviet Union are Polish diaspora who used to reside near or within the borders of the Soviet Union before its dissolution. Some of them continued to live in the post-Soviet states, most notably in Lithuania, Belarus, and Ukraine, the areas historically associated with the Polish–Lithuanian Commonwealth, as well as in Kazakhstan and Azerbaijan among others.
Painter Kazimir Malevich (Kazimierz Malewicz) was a prominent artist of Polish descent active in the Soviet Union. His attempt at settling in Warsaw in 1927 failed.
Polish refugees evacuated from the Soviet Union to Iran, 1942
The Treaty of Riga was signed in Riga, Latvia, on 18 March 1921 between Poland on one side and Soviet Russia and Soviet Ukraine on the other, ending the Polish–Soviet War (1919–1921). The chief negotiators of the peace were Jan Dąbski for the Polish side and Adolph Joffe for the Soviet side.
Second page of the treaty, Polish version