Ukrainians in Russia include all the family of hetman Ivan Mazepa, A. Vojnarovsky, and those in Mazepa's Cossack forces that returned to Russia. Some were imprisoned in exile for the rest of their lives such as hetmanPavlo Polubotok, Pavlo Holovaty, P. Hloba and Petro Kalnyshevsky. Beginning in the 19th century, there was a continuous migration from Belarus, Ukraine and Northern Russia to settle the distant areas of the Russian Empire. The promise of free fertile land was an important factor for many peasants who until 1861, lived under Serfdom. In the colonization of the new lands, a significant contribution was made by ethnic
Russia in the European energy sector which stretch beyond 2025–2030. A number of disputes in which Russia was using pipeline shutdowns in what was described as "tool for intimidation and blackmail" caused European Union to significantly increase efforts to diversify its energy sources. During an anti-trust investigation initiated in 2011 against Gazprom a number of internal company documents were seized that documented a number of "abusive practices" in an attempt to "segment the internal [EU] market along national borders" and impose "unfair pricing". Russia in the European energy sector The Russian Federation supplies a significant volume of fossil fuels and is the largest exporter of oil