Under wise administration Agriculture and Commerce, the twin pillars of national prosperity, necessarily flourished. A scientific canalisation, with irrigation works inherited from the ancients, made the Mesopotamian Valley a rival of Kemi the Black Land, and rendered cultivation a certainty of profit, not a mere speculation, as it must ever be to those who perforce rely upon the fickle rains of Heaven. The remains of extensive mines prove that this source of public wealth was not neglected; navigation laws encouraged transit and traffic; and ordinances for the fisheries aimed at developing a branch of industry which is still backward even during the xixth century. Most substantial encouragement was given to trade and commerce, to manufactures and handicrafts, by the flood of gold which poured in from all parts of earth; by the presence of a splendid and luxurious court, and by the call for new arts and industries which such a civilisation would necessitate. The crafts were distributed into guilds and syndicates under their respective chiefs, whom the government did not “govern too much”: these Shahbandars, Mukaddams and Nakibs regulated the several trades, rewarded the industrious, punished the fraudulent and were personally answerable, as we still see at Cairo, for the conduct of their constituents. Public order, the sine qua non of stability and progress, was preserved, first, by the satisfaction of the lieges who, despite their characteristic turbulence, had few if any grievances; and, secondly, by a well directed and efficient police, an engine of statecraft which in the West seems most difficult to perfect.