IN an article published several years ago we have collected evidence corroborating al-Maqrīzī's statement (mistrusted by Quatremère in Histoire des Mongols) that siyāsa, the legal code of the Mamlūks, was founded upon the Great Yāsa of Chingiz-Khān. The Great Yāsa was not merely a code of criminal and civil law but a system of rules governing the entire political, social, military, and economic life of the community which adopted it. The expansion of this system outside the Mongol nation was due to the belief that it was responsible for the extraordinary military success of the Mongols in the thirteenth century, and that it might be regarded as a talisman ensuring victories on the battle-field. The Yāsa rules concerning communal organization were even more important from this point of view than the laws treating of the behaviour of individuals. It is natural, therefore, to suppose that not only the Mamlūk criminal, civil, and commercial law but also the general organization of the Mamlūk state was based upon the Yāsa. The present article, inspired by the attempts made in modern times to collect and systematize the fragmentary evidence concerning the contents of the Yāsa, is intended to show that this organization is indeed comprehensible only in the light of such evidence. Some preliminary remarks are necessary.