Baldwin of Avesnes

Baldwin of Avesnes (1219–1295), younger son of Bouchard IV of Avesnes and Margaret II of Flanders, was declared legitimate by the pope in 1246 and received Beaumont as his apanage; his parents' marriage had been ruled illegal because his father had received minor orders.

He spent decades fighting beside his brother John I against their Dampierre half-brothers, and was blamed for the Trazegnies tournament accident that killed William III of Dampierre. After John's death he reconciled with his mother and led her expedition against Namur. In 1287 he sold Dunkirk and Warneton to Guy of Flanders. He also compiled a universal chronicle.