The confederation between Flanders and Brabant was soon consolidated.

The burghers of Bruges, who had taken the lead in the grand national union, and had been the foremost to expel the foreign force, took umbrage in 1323 at an arbitrary measure of their count, Louis (called of Cressy by posthumous nomination, from his having been killed at that celebrated fight), by which he ceded to the count of Namur, his great-uncle, the port of Ecluse, and authorized him to levy duties there in the style of the feudal lords of the high country.

It was but the affair of a day to the intrepid citizens to attack the fortress of Ecluse, carry it by assault, and take prisoner the old count of Namur.
They destroyed in a short time almost all the strong castles of the nobles throughout the province; and having been joined by all the towns of western Flanders, they finally made prisoners of Count Louis himself, with almost the whole of the nobility, who had taken refuge with him in the town of Courtrai.

But Ghent, actuated by the jealousy which at all times existed between it and Bruges, stood aloof at this crisis.

The latter town was obliged to come to a compromise with the count, who soon afterward, on a new quarrel breaking out, and supported by the king of France, almost annihilated his sturdy opponents at the battle of Cassel, where the Flemish infantry, commanded by Nicholas Zannekin and others, were literally cut to pieces by the French knights and men-at-arms.
This check proved the absolute necessity of union among the rival cities.