The abdication of Tsar Nicholas II occurred during the February Revolution of 1917, a pivotal moment in the Russian Revolution. Widespread discontent stemming from military failures in World War I, combined with economic hardships and social unrest, led to mass protests in Petrograd (now St. Petersburg). Faced with mounting pressure, Nicholas II ultimately renounced the throne on March 15, 1917. His abdication marked the end of more than three centuries of Romanov rule and set the stage for the Bolshevik Revolution later that year.