The countship of Flanders grew and got four of the largest, richest cities north of the Alps (chiefly Bruges, Ghent, Ypres) thanks to the production and trade as luxury good of the top quality of wool cloth, made form imported English wool, sought-after by the rich all over Europe, even in the East. The patrician families who controlled the trade grew richer than petty nobles, while paying the hard-working urban artisans pittance. The French king Philippe Le Bel decided to curtail the power of his richest vassal, so invaded with an occupation army. The patricians welcomed the king, hoping to be rid of comital burdens, but for the artisans it was the last straw, they rose and slew royal knights. The count's family joined them, providing military expertise in two commanders, Jan van Renesse and count Gwijde's grandson Willem van Gullik, who outsmarted the count of Artois, who commanded the royal army, the most feared in Europe, sent to crush the rebellion while breaking the siege of the fled knights in a royal castle at Courtray. The marshy conditions, motivation to fight for their lives and dismissing of the chivalry code of taking hostages for ransom earned them a s famous, the outrageous victory. Two later defeats soon undid the count's victory, but the cities granted an unprecedented say to the artisans unions.