Fedorovych, Taras [Fedorovyč] (known also as Triasylo), date of birth and death unknown. Hetman of the unregistered Cossacks from 1629, when he conducted a campaign against the Crimean Tartars. In March 1630 Fedorovych led a large peasant-Cossack revolt against Poland. His forces defeated the Polish army at Korsun and Pereiaslav and on 8 June forced the Polish hetman Stanisław Koniecpolski to sign the Pereiaslav Treaty of 1630. Fedorovych was dissatisfied with the treaty, which had been accepted by most of the Cossack leadership, and was dismissed from the post of hetman. Hence, he attempted to organize a new revolt. In 1635 he led a part of the Zaporozhian Host beyond the Don River. In 1636 he offered his services to the Muscovite tsar, who rejected the offer in order to avoid tensions with Poland.
Encyclopedia of Ukraine