 Jeremi Wiśniowiecki ( Ukrainian : Ярема Вишневецький - Yarema Vyshnevetsky ; August 17 , 1612 – August 20 , 1651 ) nicknamed Hammer on the Cossacks or Iron Hand , was a notable member of the aristocracy of the Polish @-@ Lithuanian Commonwealth , Prince of Wiśniowiec , Łubnie and Chorol in the Crown of the Kingdom of Poland and the father of the future King of Poland , Michael I. 
