Alexander Kolchak was a Russian naval officer and polar explorer who became a prominent leader during the Russian Civil War. Born in 1874, he initially served in the Imperial Russian Navy and gained recognition for his exploration of the Arctic. After the fall of the Russian Empire in 1917, Kolchak emerged as a key figure in the anti-Bolshevik movement. In 1918, he declared himself the Supreme Ruler of Russia, leading the White Army against the Bolsheviks. His forces controlled significant territories in Siberia but ultimately faced defeat. Kolchak was captured in 1920 and executed, marking a significant moment in the civil war's history.