I just discovered these details in a Library of Virginia scanned record of a Chancery Court proceeding commenced in 1812. It identifies John Jett and Robert Jett as residing in Culpeper County.
The litigation involves the estate of Robert Jett, who made a will in October 1808 and apparently died shortly after that. In the will, he identifies his brother John Jett, and three of John's children: Lavinia, James and John.
Robert had another brother Birkett D. Jett, whose wife is a plaintiff in this case along with her minor children James Jett and Benjamin Pendleton Jett. Her petition states that her husband Birkett D. Jett has "removed to Kentucky." Apparently, Birkett D. Jett had threatened to contest the will of Robert Jett, but agreed to a compromise with John Jett, executor of Robert Jett, for payment of $1,000 from the Robert Jett estate when it was settled.
John Jett filed an answer, claiming that the agreement was made under duress and besides, the estate was not yet settled. (Mildred Jett's petition states that this is because of John's negligence.) John adds that he knows little about the law and he was coerced by Benjamin Mershon, husband of a sister (unnamed; elsewhere, I found it was Ann) of John, Robert and Birkett D. Jett.
It has been a while since I have done any work on the Jetts of Virginia, but it seems to me that this establishes some relationships that previously may have not been known. Do the names ring any bells with other Jett researchers?