イェルマーク
In 1558, Ivan gave the Stroganov merchant family the patent for colonising "the abundant region along the Kama River", and, in 1574, lands over the Ural Mountains along the rivers Tura and Tobol. The family also received permission to build forts along the Ob River and the Irtysh River. Around 1577, the Stroganovs engaged the Cossack leader Yermak Timofeyevich to protect their lands from attacks of the Siberian Khan Kuchum.