The pivotal event that led to the overthrow of the Romanov dynasty in Russia during 1917 was the February Revolution. Widespread discontent over economic hardship, military defeats in World War I, and autocratic rule propelled mass protests and strikes. The abdication of Tsar Nicholas II marked the end of over 300 years of Romanov rule, ushering in a provisional government. This revolution laid the groundwork for the more radical October Revolution, which established a communist government under the Bolsheviks, significantly altering Russia's political landscape.