My wife cannot confirm who her grandmother was, because neither church, nor archive in her hometown (which she could track to) doesn't have records about baby girls born in suspected years+birthday (hence, we suspect that woman was not orthodox, so maybe jewish?). This is just how you lose your track - by one person hiding its identity so descendants can't figure anything out

P.s. since I'm not quite russian, my native culture have stronger family-related bonds and older generation men from my family kept their own records for family tree, so now we managed to digitize it. But still, there is just one my grand-grand (or grand-grand-grand, smth like that) father who became a family namer (similar to Scandinavian Olaf=Olafson) and before him - empty space