The first reference I have been able to uncover as to the two Davis's being related comes from "Fighting Rebels and Redskins: Experiences in Army Life of Colonel George B. Sanford, 1861-1892" published in 1969 by the University of Oklahoma Press. In 1862 Sanford was a 1st lieutenant in Company K, 1st U. S. Cavalry commanded by Captain Benjamin F. Davis. Sanford, who obviously knew Captain Davis, noted: He was a thorough officer" and "I am indebted to him more than any other one officer for whatever I afterwards became in the service." He also wrote on page 175 "Davis was born in Alabama and appointed to the Military Academy from Mississippi, and I believe was a distant relative of Jefferson Davis."
A second reference to the two Davis's being related appears on page 35, Volume 16 Southern Historical Society Papers where Captain Milton Rouse who was captured by Colonel Davis at Harpers Ferry noted: "Davis claimed to be a Mississippian, and a relative of Hon. Jefferson Davis."
A third reference appears in an article written for the National Tribune by O. O. Howard on July 12, 1884. Howard was writing about the Battle of Brandy Station and noted Buford's leading brigade was in charge of Colonel B. F. Davis. "Davis was a classmate of mine at West Point and a distant relative of Jefferson Davis."
I assume Benjamin Davis's being related to Jefferson Davis has morphed from these statement by Sanford et al of their possibly being related to them being either 1st or 2nd cousin in subsequent histories covering the cavalry officer.
As noted in a prior post on this blog Benjamin Franklin Davis was the eldest son of Benjamin E. Davis and Matilda Holladay Davis. Benjamin E. and Matilda were married in early 1831 in Perry County, Alabama as per county marriage indexes. Benjamin F. Davis was born in Perry County Alabama on or about the 24th of October 1831. (Davis himself notes in an August 26, 1854 letter written in acceptance of his commission as a brevet 2nd lieutenant: "My age is 22 years, ten months and two days".) 1840 Federal Census records show Benjamin E. and Matilda still living in Perry County, where the elder Davis had homesteaded, with 6 sons, the youngest of which was born about 1840. By the late 1840's the sons were living with married sisters of Matilda in Monroe County, Mississippi where a relative noted the boys were orphans.
Benjamin Franklin Davis
Matilda Davis, the daughter of Benjamin W. Holladay, was born in Wilkes County, Georgia about 1813. The family moved to Perry County, Alabama before 1830. It is not known when or where Benjamin E. Davis was born which is a huge fly in the ointment in trying to ascertain any relationship between Jefferson Davis and Benjamin F. Davis. It is also not know when or where Benjamin E. and Matilda E. Davis died, what they died of or where they are buried. I have tried in vain to locate then in any of the Perry County, Alabama cemetery records.
Jefferson F. Davis, who is probably best know as the president of the Confederate States of America although he was also a graduate of West Point, Secretary of War in the Pierce administration and both a Senator and Congressman from Mississippi, was born in Fairview, Christian (now Todd) County, Kentucky in 1808. He was the youngest of 10 children born to Samuel Emory Davis and his wife Jane (Cook) Davis. What is noteworthy about this is that Jefferson Davis is at least a generation older than Benjamin Franklin Davis even though he is the youngest child in his family.
Jefferson F. Davis
Samuel Emory Davis, Jefferson's father, was born about 1756 probably in Georgia although references also indicate he could have been born in Pennsylvania. Samuel Emory Davis was the only child of Evan Davis Jr., and his wife Mary (Emory) Williams Davis. Mary had two sons from a prior marriage who would have been half-brothers to Samuel Emory Davis. The fact that Samuel Emory Davis was an only child precludes Jefferson Davis and Benjamin Franklin Davis from being 1st cousins because to be 1st cousins you have to have grandparents in common. Second cousins are children of parent's 1st cousins. Samuel Davis would not have had any 2nd cousins on his father's side because he did not have any 1st cousins because he was an only child.
Evan Davis Jr., Jefferson Davis's grandfather, was the youngest son of Evan Davis Sr., and his wife Mary. He was born in Philadelphia about 1729. He spent some time in South Carolina before moving to Wilkes County, Georgia where he raised his son Samuel and stepsons from Mary's 1st marriage and is buried.
Evan Davis Sr., Jefferson Davis's great grandfather, was purportedly born in Wales, before 1695, although records vary on this issue. He lived in Philadelphia, Pennsylvania with his wife Mary. Evan and Mary had six children, 5 sons, Benjamin, William, Samuel, Joseph and Evan Jr., and a daughter Hannah. Records indicate William, Samuel, Hannah and Evan Jr., married where as Benjamin and Joseph did not. With all these brothers and sisters Evan Davis Jr., could have had relatives that could be related to Benjamin E. Davis, Benjamin Franklin Davis's father however without more information about Benjamin E, Davis's ancestry this possibility cannot be confirmed or denied.
In conclusion, it is safe to assume Benjamin Franklin Davis and Jefferson F. Davis are not either 1st or 2nd cousins. More information will have to become available and more research conducted to ascertain if they are related in any way. So as with many things the quest will continue.