The Russian Revolution & the Soviet experiment
From the 1917 February and October Revolutions through War Communism, the NEP, Stalinist industrialization and the Terror—the Soviet experiment as exam canon.
The collapse of the Romanov autocracy
The Russian Revolution unfolded in two distinct phases in 1917, both dated by the Julian (Old Style) calendar Russia used until February 1918. The February Revolution (8–15 March 1917 New Style) erupted from bread riots and strikes in Petrograd, compounded by catastrophic losses in the First World War and the discrediting of the court through the Rasputin scandal. When the Petrograd garrison mutinied, Tsar Nicholas II abdicated on 15 March 1917, ending the 304-year Romanov dynasty. Power passed to a Provisional Government under Prince Lvov and later Alexander Kerensky, which coexisted uneasily with the Petrograd Soviet of Workers' and Soldiers' Deputies—the condition Lenin termed dvoevlastie (dual power).
The Provisional Government made the fatal error of continuing the war (the June 1917 Kerensky Offensive failed) and delaying land redistribution. Vladimir Lenin, returned from Swiss exile in April 1917 via a sealed German train, issued his April Theses demanding "All power to the Soviets," "Peace, Land, and Bread," and no support for the Provisional Government. The Bolsheviks—a faction since the 1903 split of the Russian Social Democratic Labour Party into Bolsheviks and Mensheviks—gained majorities in the Petrograd and Moscow Soviets by September.
October and the seizure of power
The October Revolution (6–7 November 1917 NS) was an organized insurrection directed by Lenin and Leon Trotsky, who chaired the Petrograd Soviet's Military Revolutionary Committee. Red Guards seized the Winter Palace and arrested the Provisional Government. The Second All-Russian Congress of Soviets ratified the coup and adopted the Decree on Peace and Decree on Land on 8 November 1917.
The Bolsheviks lost the November 1917 elections to the Constituent Assembly (the Socialist Revolutionaries won) and so dissolved it by force on 6 January 1918. The Treaty of Brest-Litovsk (3 March 1918) exited the war at the cost of Poland, the Baltics, Ukraine, and Finland—territory later partly recovered. Civil war (1918–1921) then pitted the Bolshevik Reds against the Whites and Allied interventionists; War Communism requisitioned grain and nationalized industry, while the Cheka under Felix Dzerzhinsky launched the Red Terror. The Reds won through Trotsky's Red Army, interior lines, and White disunity. The USSR was formally constituted on 30 December 1922.
Retain these dated anchors: abdication (March 1917), April Theses, October seizure (November 1917), Brest-Litovsk (March 1918), and the founding of the USSR (December 1922). The two-phase structure—spontaneous February collapse versus engineered October coup—is the single most tested analytical distinction.