Free Catastrophe: An Investigation Into the Origins of the Modern World by David Keys Page B

composition and organization, the army of the 630s was very different from what had existed in, say, the early sixth century. Then the empire was capable of fielding substantial mobile armies with combined strengths of up to a hundred thousand men, made up mainly of regular troops. In contrast, by the end of the Persian War in 630, financial stringency, loss of manpower resources (due partly to plague), and loss of key recruitment grounds had forced the empire into a position in which it was capable of fielding an army of only thirty thousand to forty thousand men, split between various commands.
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    A nd yet soon the empire’s reduced resources and smaller military machine would be severely tested. Within five years of the end of the Persian War, a new military power was to erupt with almost volcanic intensity and suddenness from out of the sands of Arabia. Totally unexpected and extraordinarily successful, the new geopolitical force called itself Islam. 5 Within a generation it had destroyed the Persian Empire completely, reduced the Roman Empire’s size by 50 percent, and established its own empire, which would soon stretch from the Atlantic to the borders of India.
    Some early Arab historians even saw Islam’s founder, Muhammad, as a sort of new Alexander the Great. And of course today, fourteen hundred years later, Islam is still having a major political and religious impact on the world.
    Muhammad himself was very much a son of Arabia, but some of the factors that led to the foundation of the new faith, and most of the reasons for its phenomenal expansion, came from outside Arabia—from the Roman and wider worlds.
    And although Muhammad was born in c. 575 and began his ministry only around 610, many of the vital external factors that influenced him and led to his success had their genesis in the climatic disaster of that vital earlier decade, the 530s.

PART FOUR
     
    THE SWORD
OF ISLAM
     

8
     
    T H E  O R I G I N S
O F  I S L A M
     
     
    “T hey [Mankind] were wicked so We sent on them the flood of Iram [the dam of Marib] and in exchange for their two [good] gardens [We] gave them two [bad] gardens bearing bitter fruit …
    “This We awarded them because of their ingratitude …
    “They wronged themselves … therefore We … scattered them abroad—a total scattering.”¹
    Thus, according to the Koran, God spoke to his last and greatest prophet, Muhammad, sometime in the second decade of the seventh century A . D .
    The flood and the subsequent scattering of the wrongdoers almost certainly refers to a known historical event—the breaking of the greatest dam of the ancient world, that of Marib in the arid interior of Yemen.
    Up till the mid–sixth century, Yemen had been the most powerful native political force in the Arabian Peninsula. But with the destabilization of the world’s climate in the second half of the 530s and the 540s, two disasters hit Yemen.
    First, bubonic plague devastated the country—probably from 539 or 540 onward. Certainly the disease had arrived there by the 540s. And second, the agricultural economy of a key part of the country was substantially destroyed by the collapse of the Marib Dam.
    This huge structure was not one of the seven wonders of the ancient world, but it probably should have been. It was one of the largest and most spectacular feats of civil engineering achieved by humanity in premodern times. The main dam was 53 feet high, 2,046 feet long, and at least 200 feet wide at the base. Its main job was to concentrate floodwaters so that they reached a particular height and could be channeled through 2 main sluices into a 3,700-foot-long canal and thence through 15 secondary sluices and 121 tertiary sluices into a massive irrigation system consisting of hundreds of miles of canals. In total, the complex irrigated twenty-four thousand acres and supported a population of between thirty thousand and fifty thousand people.
    The city of Marib had been