In 1086, Constance's father arranged a marriage between the duke of Brittany Alan Fergant and Constance, who was already nearly 30, to ensure peace at his Western border. Like her mother, Constance was an able administrator. William of Malmesbury, an early 12th century historian, wrote that her "severe and conservative manner" made Constance an unpopular duchess. According to his contemporary, Orderic Vitalis, however, Constance was caring, considerate, and well-liked by her subjects. William of Malmesbury alleges that her husband had their servants poison her. She died on 13 August 1090.[3]
References
^Douglas, David C. (1964), William the Conqueror: The Norman Impact Upon England, University of California Press, p. 4, ISBN0300185545