"The year 1905 saw Russia submerged in a wave of mass political and social unrest, including terrorism, worker strikes, peasant unrest, and military mutinies. This led to the establishment of limited constitutional monarchy, the State Duma of the Russian Empire, the multi-party system, and the Russian Constitution of 1906.
The Russian Revolution is the collective term for a series of revolutions in Russia in 1917, which destroyed the Tsarist autocracy and led to the creation of the Soviet Union. The Tsar was deposed and replaced by a provisional government in the first revolution of February 1917, which was focused on Petrograd. The February Revolution took place in the context of heavy military setbacks during the First World War, which left much of the army in a state of mutiny.
The Soviets, which were led by more radical socialist factions, initially permitted the Provisional Government to rule, but insisted on a prerogative to influence the government and control various militias’ leading to the second revolution, during October, in which the Provisional Government was removed and replaced with a Bolshevik government.