died Aug. 6, 1584/85, Siberia
Cossack leader.
In 1579 he was enlisted by the merchant Stroganov family to defend its possessions against attacks by Siberian tribesmen. He set out with an expeditionary force of 840 Cossacks and reached the central Tatar khanate of Sibir in 1582. With their firearms, Yermak and his army defeated the numerically superior forces of Khan Kuchum and occupied the capital, Sibir. Though later killed in a revolt of Kuchum's forces, Yermak was considered the conqueror of Siberia and became a hero of Russian folklore.