Sharan Newman

 Sharan Newman is an American author, born in Michigan in 1949.  Her father was in the US Air Force.  She studied medieval history and married a physicist.. and uses her married name as a writer.  

Her first novels were a trilogy on the Arthurian story, largely focussing on Guinevere.  Guinevere is of Roman descent, and marries Arthur but falls in love with Lancelot.  Her novels came out in the early 1980s, after Marion Bradley wrote Mists of Avalon.  That novel was largely focussing on the women in the Arthurian saga and writing from a women centred, non Christian viewpoint.  It set off a trend for writing about the women in the story rather than Arthur and the men.  Newman also wrote historical mysteries set in France in the time of Abelard and Heloise.