- Roger Mortimer
Full bibliographic information is available on the Sources page
Roger Mortimer, Earl of March and Ulster
Roger Mortimer, 4th earl of March and 6th earl of Ulster, was a powerful magnate in both England and Ireland.
David Beresford, "Mortimer, Roger," in Dictionary of Irish Biography.
R.R. Davies, "Mortimer, Roger, fourth earl of March and sixth earl of Ulster" in Oxford Dictionary of National Biography.
Margaret K. Smith