Marie of Brittany, Countess of Saint-Pol
Marie of Brittany (1268–1339) was the daughter of John II, Duke of Brittany, and Beatrice of England. She is also known as Marie de Dreux. Family. Her maternal grandparents were Henry III of England and Eleanor of Provence, Henry was a son of King John of England. John was son of Henry II of England and his wife Eleanor of Aquitaine. Her sister was Blanche of Brittany, wife to Philip of Artois and mother of Margaret of Artois, Robert III of Artois and Joan of Artois, Countess of Foix. Margaret was mother of  Jeanne d'Évreux, Queen of France. Marriage. She married Guy IV, Count of Saint-Pol, in 1292, their children were as follows: Descendants. Through her daughter Mahaut, Marie was the maternal grandmother of Marie of Valois, Isabella of Valois, who became Duchess of Bourbon and was the mother of Louis II, Duke of Bourbon, and Joanna of Bourbon, who became Queen of France. Mahaut's other daughter was Blanche of Valois, who married Holy Roman Emperor Charles IV and was the mother of Katharine of Bohemia. References.