The history of the USSR is full of numerous events. This state lasted for more than half a century. Numerous events occurred during this period. The USSR was founded on territory that had previously included a large number of peoples. They represented the outskirts of the former Russian Empire. For the first time since the revolution, the union of the peoples of the Soviet republics was formed in the difficult years of civil war and foreign military intervention. The establishment of Soviet power in the territory of the former Tsar 's colonies (Belarus, Transcaucasia, Ukraine, Central Asia, etc.) experienced enormous difficulties. The most important milestones of the formation of the military-political union of the brotherly republics are considered in this article