In the course of the episode, she discovers that she is descended on her father's side from George Washington Elliott, her 3x-great-grandfather. Elliott came from New York, served as a drummer, then fought for the Union during the Civil War at Antietam and Gettysburg. Appropriately enough for the Tyler family, he remained a musician later in life.
Born 1837, according to the 1870 census, Elliott was actually a mulatto who was clearly able to pass for white, as his photo shows in later life. He was a member of Home Lodge 398 in Schuylerville, NY and obviously a Knight Templar in nearby Washington Commandery 33 in Saratoga Springs. (The historian helpfully added "They're not a cult..." Thanks so much.) Alas, both organizations are now defunct.
Just asking - how has Liv gotten to the age of 40 and not heard of Antietam? ("Oh, Gettysburg! I know that one!")
Oh never mind...
H/T to James Morgan III