At the end of the last century, the Polish historian
Jan Tengowski, having deep analysis of numerous previous studies concerning the
origin of the Zbarazh princely dynasty, rejected the possibility of the
identity of their hypothetical ancestor Fedko Nesvizhskyj and Fedir
Korybutovych. According to the historian, the family tradition of the dynasty's
origin from the Lithuanian prince Dmytro Korybut (brother of King Jagiello),
which was propagated by members of the family for centuries, must be refuted.