By 732, Islam had spread from Spain to Sumatra, and Muslim ships dominated by the Mediterranean Sea and Indian Ocean. The reasons for this rapid expansion were numerous.

a. The Persian and Byzantine empires were exhausted and could not resist Muslim attacks.

b. Many people in the lands of both the Byzantine and Persian empires favored monotheism and found the Byzantine trinity and Persian dualism distasteful. Islam was more to their liking, and they not only converted to Islam, but helped to spread it further.

c. The Muslims swept away the burdensome taxation and top-heavy government in those lands that accepted them.

d. Islam was simple to understand, and its observances were clear and unequivocal. It did not call for asceticism and condemned excesses of all kinds.

e. Conversion was a simple and straightforward matter.

f. The Muslims practiced at least a limited religious toleration, and the social and economic doctrines of Islam were far more humane than those of the other peoples of the time. Islam was a liberal force. Religious toleration in Islam consists of the recognition of the revelations given by God to the Jews, whom the Muslims call "The People of the Law," and to the Christians, who are called "The People of the Book." Muslims recognize the Jewish prophets and the Christian Jesus as having been inspired by God but accord the highest position to Muhammad as "The Seal of the Prophets," to whom God revealed his final and complete message. One should note, however, that the Qu'ran does not suggest that those who worship Idols should be tolerated. In fact, it states that they are either to be converted to Islam or face war.

g. Arabic gave the peoples of Islam a common language, and the Qu'ran gave them a common set of laws and values.

It is useful to think a moment about the nature of the Muslim expansion. Some people regard it as amazing that the relatively small and primitive - if one can use such a word in such circumstances - people as the Arabs were able to defeat powerful empires and gain control of such vast expanses of territory in so short a time. One must remember that we are talking about the Muslim expansion, not Arab conquests. The expansion of Islam was as much, or perhaps much more, a matter of religious conversion than it was of military conquest. 

The Effects of the Rise of Islam

The cultural unity of the Mediterranean, the creation and essence of the Roman empire, disappeared as a Semitic - remember that many of the inhabitants of the Byzantine and Persian empires were of Semitic stock and that their native languages were of the Semetic family - and non-Christian society established itself in the region. The trade routes connecting the eastern and western branches of Christendom were weakened as the Muslims seized control of the sea. The Carolingians turned away from the Mediterranean, and Western Europe developed in a continental semi-isolation. The region was freed from lingering influences of the Byzantine empire and was left to develop on its own.

I make this point mainly because it is the picture presented in most textbooks. The actual situation seems to have been considerably more complex and even more difficult to explain. About 750, the West, under the first Carolingians, turned their attention from Spain, Italy and the Mediterranean and the center of their culture and political power moved to northern France and Germany. At about the same time the Byzantine empire ceased to rely so heavily on its Mediterranean fleets and to base its power on land armies supported by great agricultural estates in Anatolia. Under the Ummayyad dynasty of rulers, the Muslims had been active in the Mediterranean Sea and the center of their political power was in Damascus (in modern Syria). After a civil war had driven the Umayyads from power, the new rulers, the Abbasids, moved their base of power to the new city of Baghdad (in modern Iraq) in the lands of the old Persian empire. It would appear that, for some reason, all three civilizations simultaneously decided upon a policy of disengagement. It may well have been that the unity of the Mediterranean was not broken by the incursion of the Muslims except for a short while. For the next two hundred and fifty years, it would seem that the civilizations of the region simply ignored the great waterway that lay at their front doors.

In any event, it gives one something to think about.