Facts and Events
Margaret Mortimer, Baroness Mortimer (née de Fiennes; after 1269 – 7 February 1333), was an English noblewoman born to William II de Fiennes, Baron Tingry and Blanche de Brienne. Her paternal grandparents were Enguerrand II de Fiennes and Isabelle de Conde. Her maternal grandparents were Jean de Brienne and Jeanne, Dame de Chateaudun.
Margaret had a sister, Joan de Fiennes (c. 1273 - before 26 October 1309), whose daughter, Margaret Wake, was the mother of Joan of Kent. Therefore, Margaret de Fiennes was a great-aunt of Joan, the Fair Maid of Kent. Margaret de Fiennes was also a first cousin of Humphrey de Bohun, 4th Earl of Hereford.
In September 1285, when she was fourteen or fifteen years old, Margaret married Edmund Mortimer of Wigmore, 2nd Baron Mortimer, the son of Roger Mortimer, 1st Baron Mortimer and Maud de Braose. They had eight children.