He was the Seigneur de Santes, de Willerval, de Rollancourt and de Beaumont. Santes is locate
d about 5 miles northeast of Arras just to the west of French Route 919. Guillebert was also a Knight of the Religious and Military Order of Saint Catherine of Mount Sinai. [Bonnes Nouvelles No. 14, March/Apr 1995, pg.3]
In the early 1300's he came through Flanders with about 3000 retainers and followers whom h
e brought to the assistance of the Count of Flanders Gui de Dampiere. After marrying Mahienne de Lannoy, the sole heiress of the last seigneur of Lannoy, Jean de Franchimont assumed the seigneurie de Lannoy and their issue bore the surname Lannoy everafter [Bonnes Nouvelles No. 14:pg.3, March/Apr 1995; Ghaahd p. 30]. The Franchimont coat of arms became the de Lannoy coat of arms at that time.