The existence of the communes exerted a powerful influence on the internal politics of the feudal lords of Belgium. The latter were forced to take the communes more and more into account and to change their political attitude in accordance with the wishes of the burgesses. The knights, almost ruined by the decline of the value of the land, rendered military service only when paid for it. The feudal troops were no longer sufficient in numbers. The princes were obliged to seek the aid of the cities, to beg for taxes in order to pay the loans they were now obliged to contract for the allowances of the mercenary troops which they were compelled to hire. The princes no longer governed alone; they had to respect and cultivate the friendship of the cities. Their subjects began to take part in the political combinations of the feudalists. As a matter of fact, war was no longer possible without the consent of the communes, and it resulted, therefore, that the burgesses, if in disagreement with their lord, instead of assisting him, appealed to foreign rulers and fought against their own prince. It may be said that, owing to these changes in political life, the communes had succeeded in breaking the régime of feudalism. This may be cited as a supreme instance of their importance in Belgian history. No less important was the influence they exerted--mainly during the thirteenth century--in the development of the economic, industrial, social, intellectual, and artistic life of the country. During that period trade and industry were essentially prominent in the life of the people. On account of their excellent location, the Belgian seaports became the meeting-places of vessels from the North Sea, the Baltic, the Mediterranean, the Orient. Ever since the existence of the commercial highroad between Cologne and Bruges the trade of the former had declined more and more. Given a shorter route by land, it is, generally speaking, that which is selected by merchants by which to forward their goods. Ghent became the center of commercial relations between Flanders and Germany, and many privileges were granted to Ghent tradesmen. Antwerp also grew little by little into an important commercial center, being connected with the Cologne-Bruges road by means of the Scheldt, that joins that road at Ghent.