This is very interesting as I am descended from Thomas Duty & Martha as well through their son Lemuel. From what we were told is that Martha is the daughter of Margaret Roman the wife of Thomas' uncle Russell- William and Catherine's son) from her first marriage. Martha was only 13 when she married Thomas who was 22 or 23 at the time which back then was not uncommon. We estimatd her birth year at 1785. I can definitely understand where this line gets confusing. I've got so many loops and horseshoes that I am having trouble keeping the names straight.