Biography of Ermak before the Siberian campaign is inconsistent and dubious. As N. M. Karamzin wrote, “Ermak was from an unknown family, but his soul was great”. Most of historians consider him a Don Cossack, while others assume he was a dweller of the Transurals region. He was the ataman of a Cossack gang that plundered vessels on River Volga. In 1579 when escaping from the Moscow voivodes (generals), Ermak went down the Chusovaya River to the merchants and industrialists Stroganovs.

  Employed by them for protection of their property, Ermak helped them to defend from strangers. Having obtained from Ivan IV a permit to establish outposts on rivers Ob and Irtysh (1574), the Stroganovs equipped a military expedition for protection of their possessions from the attacks of the Siberian khanate. A man of rich military experience, Ermak headed the campaign and in 1581 went to Siberia, to Rivers Tur, Tobol, and Irtysh, into domains of the Siberian khan Kuchum.

Ermak crushed resisting Tatar princelings, plundering valuables and burning houses on the way. His success was due to the firearms that Cossacks had, and the apt tactics, which made the enemies go into action where they could not use the cavalry.

Kuchum sent against Ermak an army under the leadership of his nephew, Prince Mamet-kul. In a three-day battle on October 23-25, 1582 Kuchum's army was defeated and the khanate’s capital Kashlyk was seized.

The defeat of the Siberian khanate meant a possibility of capturing the lands across the Ural Mountains. Ermak sent an ambassador to Ivan the Terrible with the news about the conquest of the new country and asked him for help. The tsar sent him 500 riflemen, but it turned to be insufficient.

On the night of 6 August 1585 (according to other data 1584) Kuchum unexpectedly attacked Ermak’s small squad, which had settled on the bank of River Vagas. The Cossack band was destroyed. The ataman, while escaping from the persecutors, tried to swim to reach a boat, but got drowned under the weight of his chain armor.

The remains of Ermak’s armed force led by M. Meshcheryak left Siberia in autumn 1585. Only two years later new Russian troops came to Siberia to continue Ermak's initiative.

Ermak's victories didn't lead to immediate annexation of Western Siberia to the Russian state. It happened much later – in the 17th century. Legends about Ermak have been reflected in painting, architecture, sculpture, and fiction.