Of all the great systems that aim at the elevation of mankind by an appeal to their religious consciousness, the latest-born is the religion preached by the Prophet of Arabia. The fundamental principles of right and wrong are common to all moral creeds; it is in their vitalising force, the life they infuse into humanity and the direction they give to human energies, that we must seek for elements of differentiation. Some have taken centuries to expand beyond their original circles, others have had to absorb foreign conceptions time after time until their primitive form became entirely changed before they could influence large masses of people. The religion of Mohammed, unaided by any extraneous help, under the impulse of a great and dominating Idea, within the space of eighty years from its birth, had spread from the Indus to the Tagus, from the Volga to the Arabian Sea. No Darius, Asoka, or Constantine came to its assistance with royal mandates and imperial homage.