Mykhailo Olelkovych [Myxajlo Olel’kovyč], b ?, d 30 August 1481 in Vilnius. Lithuanian-Ruthenian appanage prince of Slutsk and Kopyl, in Belarus; son of Prince Olelko Volodymyrovych of Kyiv and Anastasiia, daughter of Grand Prince Vasilii Dimitrovich of Moscow. In 1470–1 he served as King Casimir IV Jagiellończyk's viceroy in Novgorod the Great. When he did not succeed his late brother, Semen Olelkovych, as appanage prince and voivode of Kyiv, Mykhailo and Princes Fedir Bilsky (his cousin) and Ivan Holshansky organized a conspiracy to assassinate Casimir IV. The conspiracy was uncovered, and Mykhailo was executed for treason.
[This article originally appeared in the Encyclopedia of Ukraine, vol. 3 (1993).]