 In 1631 Wiśniowiecki returned to the Commonwealth and took over from his uncle the management of his father 's huge estate , which included a large part of what is now Ukraine . In 1632 he converted from Eastern <unk> to Catholicism , an action that caused much concern in Ukraine . His decision has been analyzed by historians , and often criticized , particularly in Ukrainian historiography . The Orthodox Church feared to lose a powerful protector , and Isaiah <unk> , metropolitan bishop of Kiev and a friend of his mother , unsuccessfully plead with him to change his mind . Jeremi would not <unk> although he remained on decent terms with the <unk> Church , avoiding provocative actions , and supported his uncle and Orthodox bishop Peter Mogila and his Orthodox Church <unk> . 
