There were many causes behind the Russian Revolution of 1917, ranging from the unpopular authoritarian rule of Tsar Nicholas II (reign 1894-1917) to the radical mobilisation of the working class, who wanted better working conditions and more political representation. Actually a double revolution, the first revolution brought about the abdication of the tsar in March, then, after the ineffective rule of the Provisional Government of 1917, a second revolution occurred in November. The latter is often called the Bolshevik Revolution because it saw the Bolsheviks (later called the Communist Party) led by Vladimir Lenin (1870-1924) seize power and establish Soviet Russia.
This is a companion discussion topic for the original content at https://www.worldhistory.org/article/2773/causes-of-the-russian-revolution-of-1917/.