Severyn Nalyvaiko
Severyn (Semerii) Nalyvaiko (Ukrainian: Северин (Семерій) Наливайко, Polish: Seweryn Nalewajko, in older historiography also Semen Nalewajko, died 21 April 1597) was a leader of an independent Ukrainian Cossack force who became a hero of Ukrainian folklore. He led the failed Nalyvaiko Uprising against the Polish–Lithuanian Commonwealth for which he was tortured and executed in Warsaw.