About the thirteenth century, the building of the city began around the castle of Amstel, on a tidal marsh. During the siege of Haarlem by the Spanish, Amsterdam depended upon its waterway for food supplies. The Duke of Alva wrote: "Since I came into the world, I have never been in such anxiety. If they should succeed in cutting off the communications along the dykes, we should have to raise the siege of Haarlem, to surrender, hands crossed, or to starve." In 1787 when the King of Prussia brought his troops to Holland, in favour of the stadtholder, Amsterdam surrendered its garrison. And in 1795 the French entered the city without the resistance of the inhabitants. Sir Thomas Overbury, who wrote in 1609, describes Amsterdam as surpassing "Seville, Lisbon, and any other mart-town in Christendom." The city maintained a great fleet of vessels trading to the East Indies, the German ports, and the towns of the Baltic Sea. The historian relates that the people were not "much wicked," though disposed to drink; they were hard bargainers, but just, thrifty, hardworking, and shrewd in commerce. To-day the natives of Amsterdam are assuredly "inventive in manufactures," and eminently capable in all affairs of trading and finance. The fishing industry has declined seriously, but the export trade of Amsterdam is enormous, the products being chiefly butter, cheese, cotton goods, glass manufactures, leather goods, bread, stuffs, and gin. In 1900 the population of the city was 523,558. Amsterdam is still a metropolis of capitalists, many of whom are of the Jewish race, while it is a principal European centre of the diamond trade. The famous banking system, established under guarantee of the city, in 1609, is described at length by Adam Smith in his "Wealth of Nations." "Public utility," he writes, "and not revenue was the original object of this institution. Its object was to relieve the merchants from the inconvenience of a disadvantageous exchange." The bank was under the control of four reigning burgomasters, who were changed every year. The opulence of Amsterdam is apparent to the stranger who roams its streets to-day. Factories abound, artificers are numerous, and everywhere there are evidences of a prosperity that recalls the day when most of the business of Europe was transacted in these narrow, twisted streets, and a large fleet of vessels traded with the Indies. Here several renowned printers set up their presses in the seventeenth century, and many famous books were printed in the city. During the following century Amsterdam still remained the great commercial capital of Europe.