Czechs began moving to what is now Ukraine in the 13th century. In the 1860s, whole colonies of Czech farmers began moving to Ukraine, mostly to Volhynia in western Ukraine. After the Russian Empire (which ruled over Ukraine back then) abolished serfdom in 1861, Czechs could buy former landowners' estates in western Ukraine at a decent cost. In 1870, Czechs (who were mostly farmers, at least initially) were allowed to become Russian subjects and almost all Volhynian Czechs eventually converted to Russian Orthodox Christianity, though some of them did remain Protestant, such as the Czech Brethren. By the start of the 20th century, the Czech population is what is now Ukraine reached 65,000. The Czechs thrived in Ukraine since they knew how to farm well and with modern farming machinery that they imported from Bohemia. After the end of World War I, the Volhynian Czechs were divided between Poland and the Soviet Union (which ruled over Ukraine back then), with around 20,000 Czechs in Poland and the Soviet Union (mostly in Ukraine and Crimea) each in the 1920s. After the end of World War II, most of the Volhynian Czechs moved to Czechoslovakia, though slightly over 10,000 of them stayed in Ukraine, mostly in Zhytomyr Oblast.