Nicholas d'Oisy, Lord of Avesnes, nicknamed le Beau ("the Beautiful") (c. 1130 – c. 1170), was a son of Walter I, Lord of Avesnes and his wife, Ada of Tournai. He was Lord of Avesnes, Leuze and Condé. He built castles in Landrechies and Condé.
Nicholas married Matilda de la Roche, the widow of Thierry de Walcourt. She was the daughter of Henry I of la Roche (c. 1100 – 1126), Count of la Roche and warden of Stavelot and Malmedy and Matilda of Limburg.
They had:
James of Avesnes, succeeded his father and died during the Third Crusade
Ida (d. c. 1205), married Ingelram, Count of Saint Pol and secondly, castellan William IV of Saint-Omer
Fastrad, warden of La Flamengerie Abbey.
