President Joe Biden has long been known for his Irish roots, but one genealogist says there’s another part of his heritage that has been overlooked: Some of his ancestors were slave owners. Alexander Bannerman, a West Virginia genealogist who has conducted a complete genealogy of the president, was quoted by Politico on Tuesday saying Census records show that several of Biden’s ancestors on his father’s side enslaved people. Two of his great-great-great grandfathers are said to have enslaved people in Maryland, including a 14-year-old boy, according to Bannerman. An article written by Bannerman and expert Gary Boyd Roberts for a magazine published by the New England Historic Genealogical Society makes no mention of slaves but does note a “distant tie” to the wife of Confederate President Jefferson Davis, Politico notes. Bannerman stressed, however, that it was not at all unusual for enslavers to turn up among Biden’s ancestors. “Not a lot of ancestors, and not a lot of slaves,” he was quoted saying of his Biden’s family tree.