?-1584

Russian adventurer who brought Siberia under Russian control. Yermak (or Ermak) was the leader of a band of outlaw Cossacks who pirated boats on the Volga River. In 1579 they were hired by a wealthy Russian family to defend their property against raids by Siberian tribes. He led a force of less than 1,000 Cossacks over the Ural Mountains and, in 1582, captured the Siberian capital, opening Siberia for eventual absorption into Czarist Russia.