Lev Davidovich Bronstein, better known as Leon Trotsky, was a Russian revolutionary, Soviet politician, journalist, and political theorist. He was a central figure in the 1905 Revolution, October Revolution, Russian Civil War, and the establishment of the Soviet Union. Alongside Vladimir Lenin, Trotsky was widely considered the most prominent Soviet figure and was de facto second-in-command during the early years of the Russian Soviet Republic. Ideologically a Marxist and a Leninist, his thought and writings inspired a school of Marxism known as Trotskyism.

The Russian Revolution of 1905, also known as the First Russian Revolution, began on 22 January 1905. A wave of mass political and social unrest then began to spread across the vast areas of the Russian Empire. The unrest was directed primarily against the Tsar, the nobility, and the ruling class. It included worker strikes, peasant unrest, and military mutinies. In response to the public pressure, Tsar Nicholas II was forced to go back on his earlier authoritarian stance and enact some reform. This took the form of establishing the State Duma, the multi-party system, and the Russian Constitution of 1906. Despite popular participation in the Duma, the parliament was unable to issue laws of its own, and frequently came into conflict with Nicholas. The Duma's power was limited and Nicholas continued to hold the ruling authority. Furthermore, he could dissolve the Duma, which he did three times in order to get rid of the opposition.