Mary of Waltham, duchess of Brittany (d. 1361)
Mary of Waltham (10 October 1344 – September 1361), Duchess of Brittany, was a daughter of King Edward III of England and Philippa of Hainault and was the wife of John IV, Duke of Brittany, known in England as "John V" and "The Conqueror". Mary was made a Lady of the Garter in 1378.