Flanders was vexed by a problem of over-population, for which neither the continuous exodus of emigrants nor the systematic reclaiming of marsh-lands offered a permanent solution. At an early date her middle-classes discovered the grand principle of modern industry: that by manufacturing for foreign markets the production of wealth can be accelerated to an indefinite degree, and the most prolific communities maintained in affluence upon a sterile or restricted territory. The superfluous labour of the Flemish countryside flocked into towns, at the bidding of Flemish capital, and found remunerative employment in the weaving trade. From 1127 onwards these towns were bargaining with the Counts of Flanders for emancipation. Bruges, Ypres, Lille and Ghent were only the most successful among forty thriving communities which, at the close of the twelfth century, enjoyed a large measure of self-government but found their liberties threatened by the King of France. To meet the danger the Flemish communes embarked on the stormy sea of politics. At first they fought the King, in the name of the Count, and made their first appearance as a military power on the disastrous field of Bouvines (1214), which cost Count Ferrand his liberty and the communes the flower of their militia. The successors of Ferrand sank deeper and deeper into dependence on the Capets, until the communes were forced in self-defence to assume the leading role. At Courtrai (in 1302) they turned the tables on the Crown, and took an ample vengeance for Bouvines, by a terrible slaughter of French knights and men-at-arms, demonstrating to a startled Europe that feudal tactics were obsolete, and that pikemen on foot were a match for the best mailed cavalry. Cheated by a treacherous Count of the due fruits of their victory, the Flemish communes nursed their resentment and waited for new opportunities, while consoling themselves with savage persecution of the nobles, the clergy, and all others whom they suspected of French sympathies. The ambition of Edward III came at length to their assistance; under the leadership of Jacques van Artevelde, a merchant-prince and demagogue of Ghent, they signed a treaty with the English King for the invasion and conquest of France (1339). It was a brief and ill-starred alliance, ruinous to Flemish trade and abruptly ended by the fall of Artevelde, whom his fellow-citizens tore limb from limb under the impression that he was aiming at a tyranny (1345). But events soon justified the bold proposals of the fallen statesman. In 1369 the heiress of the county was given to a French prince of the blood; the French party in Flanders reared their heads; Bruges, to the alarm and fury of all patriots, joined the foreign cause from jealousy of Ghent. War broke out between the two great rivals; and the men of Ghent, commanded by Philip, the son of Jacques van Artevelde, gained the upper hand. Victorious in a pitched battle,