The northern merchants dealt mainly with Venice and brought their wares across the Brenner Pass and down the Rhine, or sent them by sea to be exchanged in Flanders. By the thirteenth century important centers of trade had come into being, some of which are still among the great commercial towns of the world. Hamburg, Lübeck, and Bremen carried on active trade with the countries on the Baltic and with England. Augsburg and Nuremberg, in the south of Germany, became important on account of their situation on the line of trade between Italy and the North. Bruges and Ghent sent their manufactures everywhere. English commerce was relatively unimportant as yet compared with that of the great ports of the Mediterranean. [Sidenote: Restrictions on trade.] [Sidenote: Idea of a 'just' price.] 95. A word must be said of the numerous and almost incredible obstacles in the way of commerce in the Middle Ages. There was very little of that freedom which we now regard as essential to successful business. Our wholesale dealers would have been considered an abomination in the Middle Ages. Those who bought up a quantity of a commodity in order to sell it at a high rate were called by the ugly name of _forestallers_. It was universally believed that everything had a "just" price, which was merely enough to cover the cost of the materials used in its manufacture and remunerate the maker for the work he had put upon it. It was considered outrageous to sell a thing for more than the just price, no matter how anxious the purchaser might be to obtain it. Every manufacturer was required to keep a shop in which he offered at retail all that he made. Those who lived near a town were permitted to sell their products in the market place within the walls on condition that they sold directly to the consumers. They might not dispose of their whole stock to one dealer, for fear that if he had all there was of a commodity he might raise the price above a just one. [Sidenote: Payment of interest on money forbidden.] Akin to these prejudices against wholesale trade was that against interest. Money was believed to be a dead and sterile thing, and no one had a right to demand any return for lending it. Interest was wicked, since it was exacted by those who took advantage of the embarrassments of others. Usury, as the taking of even the most moderate and reasonable rate of interest was then called, was strenuously forbidden by the laws of the Church. We find church councils ordering that impenitent usurers should be refused Christian burial and have their wills annulled. So money-lending, necessary to all great commercial and industrial undertakings, was left to the Jews, from whom Christian conduct was not expected. [Sidenote: The Jews as money-lenders.]