The talltale in my family is that an ancestor tutored the Czar's
daughter. In truth it was probably a local gentile nobleman and that's
most likely the case in other stories of Jewish interaction with the
Czar. Of course stories where the Jew was employed for something  of
low social standing are easier to believe.
Some hints as to whether there is any truth behind the story can be
found if the family lived in an area that was otherwise exclusive to
gentiles or if they seem to have been of higher class and wealth than
other Jews. But some stories are totally made up.

Binyamin Kerman
Baltimore MD