Walbert IV was a 7th-century Merovingian count of Hainaut, born in the pagus Hainoensis of Austrasia. As a descendant of Auberon, the son of King Clodio, he served as a royal domesticus under the reigns of Clotaire II and Dagobert I. He resided at Cousolre castle, where he founded the Notre-Dame monastery. He was the father of Waltrude and Aldegund and is recognized as a saint in the Catholic tradition.