i 3 2 THE EARLY MIDDLE AGES the Holy Land and the sacred places therein. Again, they were swept back by the Emperor Heraclius, and the imminent danger that the empire would be swallowed up by them was averted. But the doom of the Persian dominion was sealed j it was to be destroyed by another power than that of the Greek Empire. The peninsula of Arabia lay cut off by the deserts from the ordinary course of the world's history. We have seen how, in the past, it had been presumably the cradle of the Semitic races which ruled over Syria and Meso- potamia. Once again it was to be the source of a great Semitic invasion. At the close of the fifth century Arabia was the vassal of Persia. Its peoples seem at intervals in Arabia. the past to have risen here and there to a com- paratively high degree of civilisation, or at least of commercial prosperity. The glories of the Queen of Sheba, who visited the court of King Solomon, are proverbial ; and Arabians had probably colonised a part of South-eastern Africa in search of gold, but they had never permanently attained to any high degree of political organisation. Dynasties had ruled among them, sometimes Jewish and sometimes Abyssinian. Debased forms of Judaism and of Christianity were known to them, but for the most part their worship was of a primitive and idolatrous order. Their most revered object of veneration was a black stone called the Kaaba, enshrined in a temple at Mecca. Mecca and Medina were the two principal cities. The bulk of the popula- tion were neither townsfolk nor agriculturists, but formed tribes living as nomads with their flocks and herds. Such was the people among whom arose the prophet whose name was to shake the world. Mohammed was a respectable person in the service of the wealthy widow Kadija, who took him completely into her favour, and she married him. When he was forty years old he saw in a vision the angel Gabriel, who instructed him as to the prophetic duties which he had been chosen to accomplish. He was to convert the Arabs to faith in one God, and the shrine of the mystic Kaaba into his shrine. The prophet's doctrine was a conglomeration of Judaism, Christianity, Fatalism, and a materialistic conception of a future life attractive enough
