Thus the Mohammedan conquest, which built an extensive Arabian Empire, ruling first in Asia, then Africa, and finally Europe, spreading abroad with sudden and irresistible expansion, suddenly declined through internal dissensions and decay, having lasted but a few centuries. The peculiar tribal nature of the Arabian social order had not developed a strong central organization, nor permitted the practice of organized political effort on a large scale, so that the sudden transition from the small tribe, with its peculiar government, to that of the organization and management of a great empire was sufficient to cause the disintegration and downfall of the empire. So far as political power was concerned, the passion for conquest was the great impelling motive of the Mohammedans. _The Religious Zeal of the Arab-Moors_.--The central idea of the Mohammedan conquest seems to have been a sort of religious zeal or fanaticism. The whole history of their conquest shows a continual strife to propagate their religious doctrine. The Arabians were a sober people, of vivid imagination and excessive idealism, with religious natures of a lofty and peculiar character. Their religious life in itself was awe-inspiring. Originally dwelling on the plains of Arabia, where nature manifested itself in strong characteristics, living in one sense a narrow life, the imagination had its full play, and the mystery of life had centred in a sort of wisdom and lore, which had accumulated through long generations of reflection. There always dwelt in the minds of this branch of the Semitic people a conception of the unity of God, and when the revelation of God came to them through Mohammed, when they realized "Allah is Allah, and Mohammed is his prophet," they were swept entirely away by this religious conception. When once {307} this idea took firm hold upon the Arabian mind, it remained there a permanent part of life. Under military organization the conquest was rapidly extended over surrounding disintegrated tribes, and the strong unity of government built on the basis of religious zeal. So strong was this religious zeal that it dominated their entire life. It turned a reflective and imaginative people, who had sought out the hidden mysteries of life by the acuteness of their own perception, to base their entire operations upon faith. Faith dominated the reason to such an extent that the deep and permanent foundations of progress could not be laid, and the vast opportunities granted to them by position and conquest gradually declined for the lack of vital principles of social order.