Catastrophe: An Investigation Into the Origins of the Modern World (10 page)

Plague had also led to the decline of urban markets, further undermining the rural economy. Rural and urban governmental infrastructure had been hit hard. Much of the government mail service and much of the highway road-station system—especially in Asia—had been closed down.² The cities’ strategic role in defense had also been undermined by the partially plague-induced population reduction.³ And the cities themselves, in their shrunken state, no doubt commanded less political authority vis-à-vis their hinterlands.

The loss of most of the Balkans to the Avars or to Avar vassals robbed the empire of one of its prime military recruitment grounds—and it is likely that plague often hit the military in their cramped barracks even more fiercely than the population as a whole.
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In terms of 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.

THE SWORD
OF ISLAM

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 the capital of the powerful kingdom of Saba (sometimes said to be Sheba in the Bible) up till the late third century
A
.
D
. and then became a major center of the united kingdom of Saba and Himyar, after ancient Saba had become subject to the Himyarites.

The worldwide climatic disruption that started in
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.
D
. 535 and lasted for up to thirty years was almost certainly responsible directly and indirectly for a series of floods and dam bursts that ultimately led to the deterioration and abandonment of the dam and the consequent collapse of agricultural production.

The deterioration of the Marib Dam complex, culminating in its final abandonment around
A
.
D
. 590, should be seen as a process spanning fifty to sixty years—a series of connected events rather than a single catastrophe. However, that process was initially triggered by the climatic chaos of the mid–sixth century, which seems to have produced not only drought but also occasional rainstorms of extreme severity. One of these freak deluges produced such massive quantities of water that, sometime in the 540s, the great Marib Dam gave way for the first time in a hundred years.

The event was recorded in a royal inscription, and a workforce from all over Yemen had to be raised to repair it, so serious was the damage. Archaeological work at the site suggests that the force of the flood was unprecedented. Certainly the authorities took unprecedented measures to try to stop it from happening again. For the first time ever, large blocks of stone were used to reinforce the dam.

Severe floods harmed the complex in two quite distinct ways: They tended to weaken or break the dam itself, and they swept thousands of tons of silt into the reservoir basin that lay behind the dam. As the basin got filled up with alluvial sediment, the distance between the basin floor and the top of the dam decreased, and it became less and less useful as a reservoir.

Geomorphological investigations at the dam have revealed that in the ten years after the dam burst in the 540s, the rate of silt deposition increased dramatically. In one part of the basin sediment levels rose nearly thirty feet in a decade. Although the parts of the basin concerned are different and therefore not fully comparable, it is striking that in the hundred or so years between the breaking of the dam in c. 450 and its giving way in the 540s, only sixteen feet of silt were deposited.

In the 550s the dam seems to have broken again. This time the silting up of the basin was so severe that the entire design of the dam complex had to be rethought. Building the dam much higher would have been one way of overcoming the sedimentation problems, but it would have been very expensive. Instead, the authorities decided to abandon the major sluice system and most of their agricultural land, opting instead to use the reservoir to water previously uncultivated land to its north. At a stroke this reduced the amount of agricultural land and food production by around 50 percent.

After the 550s Marib was therefore probably no longer capable of feeding its population, and many clans within the oasis, as well as the nomadic groups that interacted with them, would have been forced to migrate or to drastically change their annual migration patterns, respectively.

Nevertheless, the scaled-down Marib Dam complex, now watering just the area north of the reservoir, continued in use. However, the drought conditions and intermittent storms of the 530s, 540s, and 550s had combined to damage not only the dam and the reservoir but also the ecology of the highland area from which the water swept down. Drought must have killed off much of the highland vegetation; as a result, erosion increased dramatically, and more and more silt was swept down into the Marib reservoir.

Even after the climatic chaos of the mid-sixth century had subsided, it would have taken several decades for the plant ecology to fully recover and the rate of erosion and alluvial deposition to slow. The geomorphological evidence shows that silt was still being washed down in above-average quantities for part or all of the period between 560 and 590.

Thus, when floods broke the dam yet again in c. 590, the great structure was abandoned, Marib’s population fell to a fifth or a sixth of what it had been, and agricultural production at Marib declined to a mere shadow of its pre-530s level. The recently reduced population of Marib, and indeed the plague-hit population of Yemen, was simply not able to afford the increased cost of repairing the dam. Thus it was that one of the greatest engineering achievements of the ancient world passed into history.

According to both the Koran and other Arab sources, the deterioration and final abandonment of the Marib Dam did indeed force large numbers of people to leave the Marib area in search of new lands.³ Thus it was that two tribes—the Banu Ghassan and the Azd—are said to have migrated north to the Medina oasis in central Arabia.

At the same time, the climatic problems that started in the 530s were forcing the pace of change in two other ways in the Arabian Peninsula. First, the climate problems in central and northern Arabia—this time probably drought—seemed to have caused agricultural failure and famine. In Mecca—the city in which, forty years later, Muhammad was to be born—there appears to have been a serious famine, probably in the mid- to late 530s. The Mecca famine was reported by several eighth- and ninth-century Arab historians as having taken place in the lifetime of Muhammad’s great-grandfather Amr.

Although the earliest of the great Islamic historians, Ibn Ishaq, was writing 150 years after the time of Amr, the famine probably was a real historical event, as it seems to have occurred at around the time that similar famines were breaking out in many other areas of the world as a result of the global climatic problems of the 530s.

The available textual evidence suggests that the famine was so bad that, as one of the leaders of his people, Amr had to obtain wheat from as far away as Syria, and that he fed them on a sort of broth made with broken-up loaves. “Amr, who made bread-and-broth for his people—a people in Mecca who suffered lean years,” wrote a sixth- or seventh-century poet, quoted by Ibn Ishaq.

Another sixth-century poet, Wahb ibn ‘Abd Qusayy—quoted by the ninth-century historian al-Tabari—reported how Amr saved his people from the famine.

[Amr] took upon himself the responsibility which no other mortal was able to undertake.

He brought them sacks from Syria, full of winnowed wheat,

And gave the people of Mecca their fill of broken bread.

Mixing the bread with fresh meat, the people were surrounded by wooden bowls piled high whose contents were overflowing.
⁴

Another Meccan poet quoted by al-Tabari, Matrud, wrote:

Amr, who broke up bread for tharid [broth] for his people when the men of Mecca were drought-stricken and lean.
⁵

Amr’s efforts to counteract the famine seem to have—quite literally—made his name. Thenceforth he was known almost exclusively as Hashim (ostensibly after the word
hashama,
meaning “to crumble,” in commemoration of his crumbling or breaking of the bread made from the wheat he brought from Syria).