DOCUMENTATION: John Marshall (abt 1761-1806), husband of Catharina Truby Rohrer (abt 1764-1806), was the son of Andrew Marshall (died 1789 in Franklin County, Pennsylvania) and Mary Eaton Marshall (died 1818 in Guernsey County, Ohio)
A.The will of Andrew Marshall (1788/1789) names a son John; his siblings, listed in the order found in the will, were Joseph, William, Samuel, [John], Katharine, Martha and Andrew.
B.John Marshall married Catharina Truby Rohrer in Greensburg, Pennsylvania, in about 1799; and they were the parents of four children: Andrew, Samuel, John and Mary Ann (listed in birth order).
C.John Marshall and his wife both died in New Lancaster, Fairfield County, Ohio, in July and August 1806.
D.Joseph Marshall and John Patterson were appointed guardians on 12 May 1807 for the orphaned sons of John Marshall (Andrew, Samuel, John) in St. Clairsville, Belmont County, Ohio.[St. Clairsville was the home of John’s brothers Andrew Marshall and Joseph Marshall; and Belmont County may also have been the home of his sister Katharine Marshall Wilkey. The little girl, Mary Ann Marshall, was taken back to Armstrong County, Pennsylvania, and reared by her aunt and godmother Mary Ann (Polly) Truby Hovey.]
E.On 15 February 1808, two of the four brothers of John Marshall (Joseph and William; Andrew was living in Ohio and Samuel was deceased) received permission from the Legislature of the Commonwealth of Pennsylvania to sell land inherited from their father Andrew, according to the terms of his 1788/89 will. In this document, John Marshall is noted as being deceased and as having left three sons and a daughter; viz., Andrew, Samuel, John and Mary Ann.
F.By the time of the death of Mary Eaton Marshall in 1818, she, her son Andrew and his wife Margaret, and her brother or nephew Joseph Eaton all are living in or near Cambridge, Guernsey County, Ohio. The will of Mary Eaton Marshall, wife of Andrew Marshall (1818) names a deceased son John and his children, Andrew, Samuel, John and Mary Ann. 
This last document ties together the previous statements and shows without a doubt that John Marshall (husband of Catharina Truby Rohrer) is a son ofAndrew Marshall (died 1789 in Franklin County, Pennsylvania). John and Catharina Marshall were the parents of Andrew Marshall (1800-1832), Samuel Marshall (1802-1835), John Marshall (1803-1889) and Mary Ann Marshall Bailey (1804-1895).Documentation for the lives of these four individuals is significant, with family lines from Samuel, John and Mary Ann coming down to the present time.
Questions begging further research
Andrew Marshall’s date and place of birth? If he was born in Ireland, the date and place of his arrival in America?
The family of Mary Eaton Marshall? Note that an Isaac Eaton is named in Mary Marshall’s 1818 will as looking after her interests in Franklin County, Pennsylvania. Is Isaac her brother? Her nephew?
Family lines of the six siblings of John Marshall?
Where was John Marshall and what was he doing prior to his 1799 appearance in Greensburg?How did he connect with the Truby and Rohrer families, to meet and marry the widowed Catharina Truby Rohrer?Is the proximity of the Rohrer home in Hagerstown, Maryland to the Marshall home in Franklin County, Pennsylvania a factor?
 Estate File of Andrew Marshall, No. 131; The Courthouse in Chambersburg, Franklin County, Pennsylvania. Thanks to our cousins Bob and Donna Marshall for retrieving this for us last month.
 Records from the Family Bible of John Marshall and Charlotte Kelker, held for the family by Kelly Marshall (2011)
 Guardianship Bond for Andrew, Samuel and John Marshall, dated 12 May 1807 and located in the files of the Orphan’s Court for Belmont County, Ohio, at St. Clairsville.
 “An Act to Enable Joseph Marshall and William Marshall to Sell and Convey the Real Estate of Andrew Marshall, Late of Hamilton Township, Franklin County, Deceased,” The Statutes At Large of Pennsylvania 1806-1809, Vol. XVIII, Chapter MMCMXIV.Harrisburg, 1915
 Will of Mary Eaton Marshall: Will Book A, page 38; The Courthouse in Cambridge, Guernsey County, Ohio. Great thanks to the research of Jim Marshall of New Jersey (perhaps a distant cousin—not sure!) for pointing us to this Guernsey County will, which has been the certain link between John Marshall and his parents.