Industrialization deepened the pressure for Russification as well, since the construction of factories brought outsiders to Ukrainian cities from elsewhere in the Russian empire. By 1917 only one-fifth of the inhabitants of Kyiv spoke Ukrainian.19 The discovery of coal and the rapid development of heavy industry had a particularly dramatic impact on Donbas, the mining and manufacturing region on the eastern edge of Ukraine. The leading industrialists in the region were mostly Russians, with a few notable foreigners mixed in:
