Ostrianyn, Yakiv [Острянин, Яків; Ostrjanyn, Jakiv], b ? in Oster, Chernihiv region, d ca 6 May 1641 near Chuhuiv, Slobidska Ukraine. Zaporozhian Cossack hetman and leader of the anti-Polish Cossack rebellion of 1638. During the Polish-Muscovite War of 1634 he took part in battles in the Novhorod-Siverskyi region as a colonel of registered Cossacks. He participated in the 1637 anti-Polish rebellion led by Pavlo Pavliuk, and after the Battle of Kumeiky he fled to the Zaporozhian Sich, where he was elected hetman of the nonregistered Cossacks in the spring of 1638. Ostrianyn, Karpo Skydan, and Dmytro Hunia renewed the anti-Polish rebellion in Right-Bank Ukraine and Left-Bank Ukraine. On 15 May 1638 Ostrianyn’s forces routed Stanisław Rewera Potocki’s Polish army at Hovtva, between Kremenchuk and Poltava. The Poles retreated and then regrouped and attacked the encamped rebels on 13 June at Zhovnyne. Ostrianyn and some 1,000 of his followers fled to Slobidska Ukraine, and left Hunia to continue the battle for several weeks. In Slobidska Ukraine, Ostrianyn founded Chuhuiv and settled there. He was murdered by his former supporters.
[This article originally appeared in the Encyclopedia of Ukraine, vol. 3 (1993).]