No more info is currently available for Margaret Frost. Can you add to her biography?
Sources
Collins, Arthur, and Egerton Brydges. "Percy, Duke of Northumberland." Collins's Peerage of England Genealogical, Biographical, and Historical. Vol. II. London: Printed for F.C. and J. Rivington, Otridge and Son ... [et Al., 1812. 217-366. Print.
Marquis of Ruvigny and Raineval Staff. The Plantagenet Roll of the Blood Royal: Being a Complete Table of All the Descendants Now Living of Edward III, King of England. Bowie, MD: Heritage, 2001. Print.