The Russian Revolution of 1905, also known as the First Russian Revolution, was a wave of mass political and social unrest that spread through vast areas of the Russian Empire, some of which was directed at the government. It included worker strikes, peasant unrest, and military mutinies. It led to constitutional reform (namely the "October Manifesto"), including the establishment of the State Duma, the multi-party system, and the Russian Constitution of 1906. The 1905 revolution was spurred by the Russian defeat in the Russo-Japanese War. Some historians contend that the 1905 revolution set the stage for the 1917 Russian Revolutions, and enabled Bolshevism to emerge as a distinct political movement in Russia, although it was still a minority. Lenin, as later head of the USSR, called it "The Great Dress Rehearsal", without which the "victory of the October Revolution in 1917 would have been impossible".