William of Termonde

William of Termonde (1248–1311), second son of Count Guy of Flanders, held the lordship of Termonde and other Flemish lands. In 1270 he joined his father on the Eighth Crusade, and two years later led a mission asking Edward I of England to intercede with the French king over the embargo on Flemish trade.

Linked to the French crown by marriage, he stayed neutral in Guy's wars with Philip IV. After the Flemish defeat at Furnes in 1297, his family's lands were threatened. He was captured with his father in 1300 and returned to Flanders after four years; William died in 1311.