William I (1324 – 1 October 1391), also called the Rich, was Count of Namur from 1337 until his death.
[1] William participated in the Hundred Years' War on the side of the English.
Thanks to the fortune, first of his mother and then of his wife, William was able to buy several territories which enlarged the Marquisate.
He first married on 13 February 1348 with Jeanne of Hainault, daughter of John of Beaumont and Margaret of Soissons.
William remarried in March 1352 with Catherine of Savoy, daughter of Louis II of Vaud and Isabella of Châlon.