The primary cause of the Russian Revolution in 1917 was a culmination of social, political, and economic unrest exacerbated by World War I. The Russian Empire faced severe military failures, food shortages, and widespread discontent among the working class and peasants. The February Revolution led to the abdication of Tsar Nicholas II, ending centuries of Romanov rule. Subsequently, the Bolsheviks, led by Vladimir Lenin, seized power in the October Revolution, promoting a radical transformation of Russian society. The revolution ultimately resulted in the establishment of a communist government, drastically altering the political landscape both in Russia and internationally.