{304} CHAPTER XIX ARABIAN CONQUEST AND CULTURE The dissemination of knowledge, customs, habits, and laws from common centres of culture has been greatly augmented by population movements or migrations, by great empires established, by wars of conquest, and systems of intercommunication and transportation. The Babylonian, Assyrian, Persian, Alexandrian, and Roman empires are striking examples of the diffusion of knowledge and the spread of ideas over different geographical boundaries and through tribal and national organizations; and, indeed, the contact of the barbarian hordes with improved systems of culture was but a process of interchange and intermingling of qualities of strength and vigor with the conventionalized forms of human society. One of the most remarkable movements was that of the rise and expansion of the Arabian Empire, which was centred about religious ideals of Mohammed and the Koran. Having accepted the idea of one God universal, which had been so strongly emphasized by the Hebrews, and having accepted in part the doctrine of the teachings of Jesus regarding the brotherhood of man, Mohammed was able through the mysticism of his teaching, in the Koran, to excite his followers to a wild fanaticism. Nor did his successors hesitate to use force, for most of their conquests were accomplished by the power of the sword. At any rate, nation after nation was forced to bow to Mohammedanism and the Koran, in a spectacular whirlwind of conquest such as the world had not previously known. It is remarkable that after the decline of the old Semitic civilization, as exhibited in the Babylonian and Assyrian empires, the practical extinction of the Phoenicians, the conquest of Jerusalem, and the spread of the Jews over the whole world, there should have risen a new Semitic movement to disrupt {305} and disorganize the world. It is interesting to note in this connection, also, that wherever the Arabs went they came in contact with learned Jews of high mentality, who co-operated with them in advancing learning.