Mary Pershall, who writes under the pen name "Susan Shelley," is an author of over 20 novels , including a series of historical romances about the family of William Marshal:
A Shield of Roses (1984) about Sir Richard fitzGilbert de Clare and Lady Eve MacMurrough, the parents of Isabel de Clare
Dawn of the White Rose (1985) about William Marshal and Isabel de Clare, the parents of William fitzWilliam Marshal
A Triumph of Roses (1986) about William fitzWilliam Marshal and Eleanor Plantagenet, daughter of King John and sister of King Henry III
Roses of Glory (1987) about the fictional Giles, son of William fitzWilliam Marshal