Kennedy summarizes his argument thus: "In the final analysis, the success of the Muslim conquest was a result of the unstable and impoverished nature of the whole post-Roman world into which they came, the hardiness and self-reliance of the Bedouin warriors, and the inspiration and open quality of the new religion of Islam." Significantly, his very plausible list of factors ends rather than begins with the motivating power of Islam. His book gives no support to those who see the story of Islam as an incessant tale of bloodshed and massacre in the guise of holy warfare, and he is very fair in quoting contemporary observers who saw both the good and bad sides of the new regime. Christian critics easily distinguished between those Arab rulers, like the Caliph Yazid II, who were monstrous tyrants, and the others who were decent and just. The Arabs varied enormously in their treatment of Christians, Jews, and other conquered peoples, and it is hard to generalize over the whole region. As Kennedy notes, however many people may have disliked the new regime, few moved to active resistance: "The fragmented nature of the response of the conquered was an important reason for the success of the Muslims, both in the initial conquest and in the consolidation of their rule."
Critically too, it is useful to be reminded that most contemporaries saw their new masters as a social or ethnic category, rather than a religious movement. In Mesopotamia, the central political division was not between Muslims and Christians but rather between Arab masters and Suriani [Syrian] subjects, and the latter happened to be Christian. In Egypt, Arabs confronted a majority of Copts, that is, native Egyptians. This was an Arab conquest, rather than a Muslim one. Indeed, Kennedy devotes surprisingly little attention to acknowledging the widespread modern theories suggesting that Islam emerged as a separate religion decades later than the official accounts say, and that the first Muslims located themselves on the same theological spectrum as Christians and Jews. This question about the nature of Arab religious identity during the first wave of conquest is of course vitally important, as it would have affected the attitudes of the conquered nations, in which Muslims remained an élite minority for at least for two hundred years after the initial takeover. Whatever the real roots of Islam, Kennedy reminds us how open the early conquerors were to using non-Muslims as administrators, especially under the Umayyad dynasty that held power from 661 to 750.
Also making the transition of power easier, it was far from obvious for the first two centuries that the Arab conquest would mark a permanent transformation, rather than a passing phase: countries like Syria and Egypt were well used to transient empires. History also suggested that the Roman Empire tended to strike back very successfully against intruders, even though retaliation might take centuries. Of all the barbarian invaders who had seized portions of the Western Empire in the 5th century, the Byzantines conquered or expelled some, while the others all accepted Catholic Christianity by the 8th century. After seeing the Persians overrun their whole Eastern Empire by 616, the Romans had staged a stunning comeback in which they in turn destroyed Persian power. Even when Roman armies were not obviously in the neighborhood, the empire had an impressive ability to project its power through allies and proxy states, making great use of diplomacy and intelligence. The Muslims suffered a traumatic setback in 717-18, when the Byzantines threw them back from the approaches to Constantinople. Adding to the shock, the Romans owed their victory to their secret weapon, Greek Fire, a kind of napalm that wrought havoc with enemy ships, and which must have had a daunting effect on apocalyptically minded Muslims. Hadith composed about this time suggest real concerns that a revived Byzantine and Christian power might be able to roll back Islam to Mecca and Medina. As late as the 10th century, these prophecies seemed on the verge of fulfillment when the Byzantines reoccupied most of Syria and northern Mesopotamia and approached the gates of Jerusalem and of Baghdad itself. They were stopped only by the manpower shortage that was the eternal curse of later Rome.






