Which preposition to use with ancestress

of Occurrences 14%

My sonmyown" Immovable there, her arms flung up and tears so heavy that they rolled whole from her face down to the black grenadine, she was as sonorous as the tragic meter of an Alexandrine line; she was like Ruth, ancestress of heroes and progenitor of kings.

with Occurrences 1%

Yet if they had only been able to claim some ancestor with a wig and a degree for the humanities, or some beautiful ancestress with a romantic reputation!

Which preposition to use with  ancestress