I have just read in Letitia Dabney Miller's memoirs (found in several libraries, but I consulted them at the McCain Library at the University of Southern Mississippi, Hattiesburg) that a slave named Henry was a boy in their family during the Civil War. Letitia was Captain Frederick Yeamans Dabney's youngest sibling. Thus, Henry belonged to Philip Augustine Lee Dabney, their father. This Henry could be the John Henry of legend. If so, Captain Dabney would have known him when he was a child. Captain Dabney would have been about 15 years older.