The First World War marked a turning point in the Russian history. The country entered the war in August 1914 as an empire, and in 1918, when the war ended, its name was: the Russian Soviet Federative Socialist Republic. In 1917 it confronted two revolutions – the February and the October Revolutions. As a result of the October Revolution, the Bolsheviks ruled the country and began the construction of a new type of state. In 1918 a civil war broke out, which was largely over in 1920, but in some areas continued until 1922. In the end of 1922 the USSR was formed ‒ the Union of the Soviet Socialist Republics. In this article we analyze the impact which these events had on academic and mathematical life. We discuss the mathematical schools of St. Petersburg and Moscow, mathematical centers in Kazan Kharkov, Kiev and Odessa, academic institutions relocated inland (University of Warsaw ,Riga Polytechnics) and others. We also mention mathematicians immigrants from Russia, who became a common phenomenon in mathematical communities of other countries.