The growing power of Russia in the West began to undermine the Siberian Khanate in the 16th century. First, groups of traders and Cossacks began to enter the area. The Russian Army was directed to establish forts farther and farther east to protect new settlers from European Russia. Towns such as Mangazeya, Tara, Yeniseysk and Tobolsk were developed, the last being declared the capital of Siberia. At this time, Sibir was the name of a fortress at Qashlik, near Tobolsk. Gerardus Mercator, in a map published in 1595, marks Sibier both as the name of a settlement and of the surrounding territory along a left tributary of the Ob. Other sources contend that the Xibe, an indigenous Tungusic people, offered fierce resistance to Russian expansion beyond the Urals. Some suggest that the term “Siberia” is a Russification of their ethnonym.
By the mid-17th century, Russia had established areas of control that extended to the Pacific. Some 230,000 Russians had settled in Siberia by 1709. Siberia was a destination for sending exiles.
The first great modern change in Siberia was the Trans-Siberian Railway, constructed during 1891–1916. It linked Siberia more closely to the rapidly industrialising Russia of Nicholas II. Around seven million people moved to Siberia from European Russia between 1801 and 1914. From 1859 to 1917, more than half a million people migrated to the Russian Far East. Siberia has extensive natural resources. During the 20th century, large-scale exploitation of these was developed, and industrial towns cropped up throughout the region.