Yermak Timofeyevich (?-1585) was a Cossack bandit who ended up conquering Siberia for Tsarist Russia.

The leader of a band of Cossack brigands, Yermak spent his early years plundering merchant vessels on the Volga River. Eventually he turned respectable, entering the service of a prominent merchant family, the Stroganovs, who sent Yermak on an expedition to protect their trade in western Siberia from attack by local tribes. Advancing in river boats, Yermak and his band crossed the Urals and despite their small numbers, captured the capital of the Tartar Khanate of Sibir in 1582, thanks to the tactical superiority provided by their advanced firearms.

Not knowing what to do with his new kingdom, Yermak claimed the conquered territory in the name of Tsar Ivan IV and appealed to the Tsar for aid. Yermak was killed a few years later in a battle with the Tartars, and his troops were forced to retreat, but now that the Tsar considered Siberia as one of his possessions he sent in an army which retook the territory in 1586, and Siberia has been part of Russia ever since.