The Liber de Restauratione Sancti Martini Tornacensis names "Fastridus filius eius [=Fastredus]", and in a later passage specifies that he was "filius illius Ide" and "advocatus Tornacensis". Another perspective on the parents of Gauthier [I] d’Oisy is provided by the late 13th century genealogy by Balduinus de Avennis which records that "nepos suus ex sorore Walterus cognomina Plukellus" succeeded "Goswinus de Oysiaco, castellanus Cameracensis". It is not known which version might be correct.
Avoué of Tournai.
Married Richilde, daughter of ---. The Liber de Restauratione Sancti Martini Tornacensis names "Richilde" as wife of "Fastradus", without giving her origin, specifying that she became a nun at Tournai after her husband's death. Her family origin has not been traced. However, the [1205] Chronicle of Liessies abbey records that Baudouin IV Comte de Hainaut was guardian of “trois Gillion, enfants nobles, dont les pères étaient morts...de Chimay...de Bousignies [Bouchain] et...de Trazegnies”, noting that the last named was claimed by “Gautier d’Avesnes avec lequel il était plus proche parent qu’avec le comte”. The precise family relationship between Gilles [I] de Trazegnies and Gauthier [I] d’Oisy Seigneur d’Avesnes has not been ascertained: maybe it was through Gauthier’s mother. 1
Research Notes: