The primary cause of the Russian Revolution, which culminated in 1917, was widespread dissatisfaction with the existing autocratic regime under Tsar Nicholas II. Various factors contributed to this discontent, including military failures in World War I, economic hardship, food shortages, and social inequalities exacerbated by rapid industrialization. The inability of the Tsar to address these grievances led to the February Revolution, which resulted in his abdication. Later, the October Revolution, led by the Bolsheviks under Lenin, established a communist government. Underlying ideological tensions and the desire for social change also fueled the revolution, marking a significant shift in Russian society and politics.