The author of capital work zaglavіem "Rod Gredimina" Іosif Wolf, ending his izsldovanіe about the descendants of Prince Fyodor Olgerdovich, among others says: "Even in the beginning of the XVII century. false predanіe about the proiskhozhdenіi of the princes did not die out. Sangushkov from Lubart. Stryykovskіy, following the chronicle of Bykhovets, withdraw them from the sixth Olgerdov son Fedor Sangushko. The same mnnіya holds Paprotskіy. In the XVI and even in the beginning of the XVII century. Sangushki are Olgerdovich.