The commercial policy of the Turks, now well established, was not at all one of hostility to trade. They sought indeed to exclude foreigners from their internal commerce, as well as from the conduct of through trade while crossing their lands.[22] But such a desire cannot rightly be counted against them; all states endeavour to protect the pockets of their subjects. In conquering new regions the Turks regularly renewed the old commercial treaties with foreign powers, and usually observed them faithfully.[23] It is true that with them commerce was secondary, and conquest stood first. But they wished to encourage trade for the sake of revenue.[24] They fought with Genoa and Venice, not because these were trading powers, but because they owned lands, cities, and exceptional rights within the area of Turkish political influence. With Florence, Ancona, and other commercial cities which had no lands in the Levant and strove for none relations were uniformly good.[25] The Turks even confirmed or granted privileges of trade in their ports beyond what were allowed in the West, and some of their rules as regards duties were more liberal than elsewhere.[26] But no doubt generous provisions were not infrequently frustrated in particular cases by grasping officials, who, by the way, were usually renegade Christians.[27] After his conquest of Trebizond Mohammed II came into conflict with Venice in 1464 and took some of her Levantine territory. War followed for nine years, in the course of which a new route of Eastern trade was temporarily opened.[28] The Venetians formed an alliance, both military and commercial, with the Turkoman Uzun Hassan, and some regions of southern Asia Minor, which had not been recovered by the Ottoman Turks since the time of Timur, furnished an opening through which spices could pass for a short time to Satalia, the present Adalia. Mohammed, however, annexed the southern regions, inflicted a severe defeat upon Uzun Hassan, and forced the Venetians to a favourable peace. Soon after this he took the Genoese possession of Kaffa in the Crimea, subjugated the Tartars of that neighbourhood, and obtained complete control of the Black Sea. The trade to the East through that sea was already practically gone. Some Genoese remained in Kaffa, and the Venetians obtained sailing and trading rights which were continued formally for sixty years.[29] But for about three centuries the Black Sea was used by hardly any other ships than those of the sultan’s subjects. A considerable trade upon it supplied Constantinople with food and various raw materials, some of which were exported to the West.[30] The conquests of Mohammed II undoubtedly contributed in some degree to the obstruction of the northern routes, but their importance, both in time and extent, was secondary. What measure of reduction they accomplished in the Levant trade at the north served to increase the trade along the