 After they failed to take the besieged castle of Cassel, they marched onto Kortrijk (Courtrai) where a Flemish makeshift army was gathering to stop a French army under the command of Robert II of Artois.This battle, won by a motley alliance of Flemish and Namur petty nobles and many commoners, was later famously called the Battle of the Golden Spurs.In 1309, together with Jan Breydel and Jan Heem, he led a new uprising in Bruges, this time against the adverse effects (for Flanders) of the peace of Athis-sur-Orge (1305).