Koran, the name given to the book which contains Mohammed's revelations, used originally for each distinct one, and now for the volume containing them all. According to the Moslem creed, the Koran is a block of stone, resting by the throne of the Almighty, on which is written all the laws, portions of which are supposed to have been told to Mohammed both at Mecca and Medina, either by Gabriel in human shape or by God Himself. Mohammed dictated verses and chapters to a scribe, who wrote on palm-leaves, skins, blade-bones, and the breasts of men, which were thrown carelessly into a box, so that many were lost. After Mohammed's death they were collected into a volume by Zaid Ibn Thabit, his secretary. In the thirtieth year of the Hegira, Calif Othman had new copies made, placing the 114 suras (" chapters") in descending order as to length. The principal tenets are that there is one God, one true religion, one Day of Judgment. There are said to be more than 20,000 different commentaries on it.