Plagues and Peoples

by William H. McNeill

  In other parts of the Islamic world, major bouts of bubonic plague often lasted for several years, shifting from town to town or region to region with the seasons, but persisting as an unbroken chain of infection until susceptible human hosts ran out and the pestilence disappeared for a while. As in Europe, such visitations of plague tended to affect any given region at irregular intervals of twenty to fifty years, i.e., after a new human generation had arisen to replace those who had been exposed to the infection before.70

  Moslem response to plague was (or became) passive. Epidemic disease had been known in Arabia in Muhammad’s time, and among the traditions that Islamic men of learning treasured as guides to life were various injunctions from the Prophet’s own mouth about how to react to pestilential outbreaks. The key sentences may be translated as follows:

  When you learn that epidemic disease exists in a county, do not go there; but if it breaks out in the county where you are, do not leave.

  And again:

  He who dies of epidemic disease is a martyr.

  And still again:

  It is a punishment that God inflicts on whom he wills, but He has granted a modicum of clemency with respect to Believers.71

  The effect of such traditions was to inhibit organized efforts to cope with plague, though the word here translated as “epidemic disease” presumably applied to other forms of pestilential disease in Muhammad’s own time—smallpox, perhaps, in particular, outbreaks of which seem to have preceded and accompanied the first Moslem conquests of Byzantine and Sas-sanian territories.72

  By the sixteenth century, when Christian rules of quarantine and other prophylactic measures against plague had attained firm definition, Moslem views hardened against efforts to escape the will of Allah. This is well illustrated by the Ottoman Sultan’s response to a request from the imperial ambassador to Constantinople for permission to change his residence because plague had broken out in the house assigned to him: “Is not the plague in my own palace, yet I do not think of moving?” Moslems regarded Christian health measures with amused disdain, and thereby exposed themselves to heavier losses from plague than prevailed among their Christian neighbors.73

  In the Balkans and nearly all of India, where Moslems constituted a ruling class and lived by preference in towns, this turned into a demographic handicap. After all, exposure to most infectious diseases was intensified in towns. Only a steady stream of converts from the subject populations could countervail Moslem losses from plague and other infections. When in the Balkans (though not in India) conversion slowed almost to a halt in the eighteenth century, the human basis for Moslem dominion speedily began to wear thin in regions where the rural, peasant population remained of a different faith. National liberation movements among Balkan Christian peoples could not have succeeded as they did in the nineteenth century without this underlying demographic impetus.

  As for China, from the fourteenth century onward that vast country possessed two frontiers vulnerable to plague: one to the northwest, abutting on the steppe reservoir, and one to the southwest, abutting on the Himalayan reservoir. Available records, however, do not make it possible to distinguish bubonic plague from other lethal epidemic diseases until the nineteenth century, when outbreaks in Yunnan, connected with the Himalayan reservoir, eventually broke through to the coast in 1894, with world-wide consequences already described. Before 1855, lethal infections were common enough in China; and many outbreaks were probably bubonic. But available information does not allow more definite statement. All the same, the halving of China’s population between 1200 and 1393 is better explained by plague than by Mongol barbarity, even though traditional Chinese historiography preferred to emphasize the latter.74

  Nor can China have been the only part of Asia to suffer from plague losses. Throughout the lands north of the Himalayas, it is reasonable to suppose that significant population decay occurred in the fourteenth century, when the steppe exposure to bubonic infection was still new, and local human adjustments to the risk of mortal infection had not yet had time to work themselves out. But information is almost wholly lacking, save for a very few scattered, casual remarks that modern scholars happen to have picked up. Thus, for example, an Arabic writer reported that before the plague reached Crimea in 1346 and began its devastating career in Mediterranean lands, Uzbek villages of the western steppe had been completely emptied by the disease.75

  If we think instead of the eastern portions of the steppe, the fact that the decay of the Mongols’ power, signalized by their retreat from China in 1368, followed rather closely on the presumed spread of Pasteurella pestis throughout the steppe is very striking. One may, surely, wonder whether intensified exposure to disease, and especially to bubonic plague, was not a real factor in undermining Mongol military might. If the hypothesis presented here is correct, it is hard to doubt that steppe nomad populations, all the way from the mouth of the Amur to the mouth of the Danube, suffered population decay as a consequence of their new exposure to highly lethal infection. If so, one can see why replenishment of military manpower needed to sustain the Mongol hegemony over settled populations—whether in China, Persia, or Russia—faltered, and how the processes accelerated whereby nomad overlords were overthrown and/or absorbed by their erstwhile agricultural subject populations across all of Asia and eastern Europe.

  Such a demographic disaster—if such it was—also would account for the decay of urban centers on the steppe, where trading cities had assumed considerable significance in the early part of the fourteenth century. The destruction of cities on the Volga has usually been attributed to the ruthlessness of Timur the Lame (campaigned 1369–1405). Timur assuredly did transfer artisans en masse to his capital at Samarcand; and he plundered, killed, and burned far and wide in India, Asia Minor, and across the western half of the Eurasian steppe. But the ravages of such a conqueror were nothing new; and devastated cities recovered quickly, if a suitably populous rural base from which to attract new inhabitants lay at hand. This appears to have occurred in Asia Minor and in India in Timur’s wake; it did not happen in the western steppe.

  The intrinsic fragility of caravan linkages upon which the prosperity of these cities depended may explain this failure: successful organization of long-distance trade, after all, required favorable conditions across broad territories, and excessive macroparasitism or any other serious malfunction at any point in the system could quickly disrupt costly caravan movement of goods. This may adequately explain why recovery from Timur’s ravages in the grasslands of western Asia was so slow as to be imperceptible. Yet altered patterns of microparasitism may have played the really critical role. In fact, political disorder in the steppe after 1346 may perhaps have been a violent and shortsighted response on the part of rulers accustomed to a higher level of income than could any longer be provided by plague-riddled merchants and artisans whose more numerous and prosperous predecessors had supported all earlier efforts at state-building in central Asia and eastern Europe by paying heavy taxes.

  We may be sure that personnel who made a living by assembling goods, protecting them in transit, and buying and selling en route or at the caravan termini, were particularly vulnerable to plague. Especially in the decades when the disease was novel, so that tried-and-true rules for coping with it were lacking, heavy die-offs may have done much to destroy the caravan network that had sprung into existence throughout the Eurasian grasslands in the wake of Mongol conquests. It is ironical to reflect that if this reconstruction of events is well founded, the very success with which the Mongols exploited the military potentialities of steppe life exposed Eurasian nomadry to epidemiological disasters from which the nomad warriors, herdsmen, and traders of Eurasia were never to recover.76

  This hypothesis of demographic disaster on the steppe is rendered more plausible by another obvious yet little considered change in the human ecology of Eurasia—a change that becomes unmistakable after the fourteenth century. Prior to that time, for more than three thousand years, ste
ppe populations had persistently taken advantage of their superior mobility and military prowess to expand southward into agricultural, civilized regions. They came sometimes as conquerors, sometimes as slaves, sometimes as mercenaries; but the drift off the steppe and into the Eurasian agricultural world was unmistakable and persistent. From time to time it became massive enough to alter linguistic and ethnic boundaries in lasting ways. The distribution of Indo-European and of Turkish languages is testimony to the magnitude and persistency of this process. Moreover, in the centuries before 1300, movement from the steppe had attained a particularly massive scale, as Seljuk and Ottoman expansion, capped and climaxed by the Mongol storm itself, surely proves.

  Yet after 1346 this pattern of migration disappeared and by the sixteenth century the drift of population on the western steppe had clearly reversed itself. Instead of nomads pressing outward from the grasslands and encroaching on cultivated ground, as had been happening for millennia, by 1550 at the latest, agricultural pioneers began to penetrate the western steppelands. They moved into what had, for the most part, become an uninhabited sea of grass.

  The deserted condition of Europe’s grasslands in late medieval and early modern times must be seen as a problem to be explained, though historians have usually been content to accept the situation of 1500 as “normal.” But the Ukrainian steppe was excellent farmland, as Russian cultivators soon showed. It was equally promising as a habitat for nomads, offering the best pasture anywhere west of Mongolia. Why, then, was it almost devoid of human life in early modern times? Raiding, especially slave raiding, certainly served to diminish human numbers, once it assumed organized form in the late fifteenth century. Ottoman slave markets were limitless. Tartar horsemen of the Crimea capitalized on this fact by attacking Russian villages, traversing miles of emptiness before they could find suitable human victims. But such slave raiding does not explain the emptiness of the steppe itself. Where had nomads and their herds gone?

  Withdrawal to the Crimea, and partial urbanization in that specialized environment may represent a deliberate choice on the part of those who made such a withdrawal. It allowed closer contact with Ottoman civilization and all the delectations civilization involved. But it is impossible to believe that nomad inhabitants of the rich grasslands of the Ukraine could all have fitted within the narrow confines of the Crimea unless some prior, massive disaster had radically diminished their numbers and made the defensible bastion of the Crimean peninsula look especially attractive to the remnant.77

  Inferential evidence from the eastern reaches of the steppe suggests that the peoples of Mongolia and Manchuria learned how to insulate themselves effectually against plague by the seventeenth century or earlier. Otherwise, the Manchu conquest of China in the 1640s, which matched older steppe invasions exactly, could not have taken place. Lasting success required a relatively numerous and disciplined military force of Manchu “banner men” to support the new dynasty.

  Simultaneously, among Mongols and Tibetans, a vigorous religious and political movement manifested itself in the seventeenth century—the rise of the so-called “Yellow Church” of Lamaistic Buddhism. The resulting reorganization of nomad society was sufficiently formidable that the new Manchu rulers of China had to concern themselves with it from the 1650s. Eventually the Manchus used China’s vast resources to sustain campaigns of conquest that added Tibet and Mongolia to their empire. This required substantial effort, however, and definitive success did not come to Chinese armies until 1757, when smallpox disrupted the last fighting confederacy of the steppe, led and organized by Kalmuks.

  This military-political record implies that by the middle of the seventeenth century the peoples of the eastern steppe retained or regained numerical strength sufficient to sustain their traditional roles vis-à-vis settled Chinese society. How this occurred cannot, of course, be known. But, as we have seen already, by the time medically trained observers became aware of the ecology of Pasteurella pestis and could study its relationship with humans, marmots and the other burrowing rodents of Manchuria and Mongolia, effective folkways had indeed developed to make human infection unlikely. If we assume that these customs date back to the seventeenth century (or before), the revival of political-religious-military expansiveness among the peoples of the eastern steppe becomes intelligible.

  By contrast, the nomads of the western steppelands, falling as they did under Moslem influence, may have accepted plague as irremediable. They also had to cope with a different rodent population than existed in the eastern steppe; and this may have made the development of suitably protective folkways more difficult. At any rate, it is clear that bubonic infections did continue to break out in eastern Europe at frequent intervals throughout modern times, down to and including the twentieth century. By way of contrast, the only recent plague outbreak in the Far East was, as we saw, the work of ignorant Chinese immigrants moving into an unfamiliar environment where they disregarded nomad customs that were quite adequate, if carefully observed, to protect the human populations from infection.

  The disease disasters that probably decimated the people of the steppes in the thirteenth to fifteenth centuries were soon followed by two additional blows: first, the circumnavigation of Africa by European seamen (1499), followed by the systematic opening up of a sea route between Europe and the other major centers of civilized population. Thereafter the caravans of the steppelands were no longer the cheapest way to carry Chinese goods to Europe and vice versa. One of the sustaining impulses for overland movement of goods thenceforth disappeared, and the basis for any economic revival on the steppes diminished accordingly. This was in turn followed in the seventeenth century by the development of effective hand guns that made the traditional archery of steppe cavalry ineffective against well-trained infantry. Partitioning of the Eurasian steppelands between adjacent agricultural empires swiftly and ineluctably followed, with Russia and China the principal beneficiaries.78

  It is therefore tempting to suppose that the major consequence of the changed distribution of bubonic infection in Eurasia was the disembowelment of steppe society. There is small likelihood of ever being able to find documentary support for such a view. On the other hand, Chinese, Islamic, and perhaps even Indian documents, if they were to be carefully perused by linguistically competent scholars sensitive to the question, probably would provide a basis for reconstructing population and disease history of those societies with approximately the same degree of precision that obtains today with respect to Europe. But since the necessary painstaking labor has not even begun, general statements about the population history of Asian societies other than China before the eighteenth century lack any satisfactory basis. Even for China, study of local records will be needed to assess the importance of disease in cutting back China’s population by more than 50 per cent between 1200 and 1400.

  Farther away from the new focus of infection in the steppes, human responses to the changed disease pattern probably weakened. In India, for instance, if that subcontinent was in fact one of the most ancient homes for chronic plague infection among communities of burrowing rodents, the changes wrought farther north by the Mongols would make little difference. The same is true of even more distant sub-Saharan Africa. Habits and customs that restricted human plague to bearable proportions had presumably defined themselves in both these regions in ancient times, when plague first went aboard ships and began to spread through the Indian Ocean and adjacent seas. Consequently, any additional exposure to Pasteurella pestis that may have filtered down from the North, across the Egyptian land bridge or by some other route, would make little difference to the plague-experienced peoples of Africa and India. The fact that there seem no special signs of any population crisis in India in the fourteenth century is not therefore surprising; though the almost total absence of documentation really makes this, and any alternative speculation, almost pointless. Plague did exist in India and east Africa between 1200 and 1700. How serious it may have been, no one can say.

&n
bsp; What we see, then, as the over-all response to the changed communications pattern created in the thirteenth century by the Mongols is a recapitulation of what we saw happening in the first Christian centuries. That is to say, massive epidemics and attendant military and political upheavals in Europe and (less clearly) also in China led both in the early Christian centuries and in the fourteenth century to sharp diminution of population in the Far East and in the Far West; but in the regions between, both epidemic history and population history are difficult or impossible to discern. In the earlier instance, several diseases were probably at work, and it took a longer time for population to recover, especially in Europe. In the fourteenth century, on the contrary, a single infection was probably responsible for most of Europe’s population decay, and recovery both in Europe and in China was swifter, so that by the second half of the fifteenth century unmistakable population growth again set in at each extreme of the Old World ecumene. Even in Muscovy and the Ottoman empire, lands lying close by the steppe focus of plague infection, population growth became unmistakable in the sixteenth century, perhaps beginning even earlier.79

  Before the limits of that renewed growth had been attained, a fresh disturbance to ecological and epidemiological world balances set in as a result of the discovery of the New World by Europeans. Consideration of the drastic and dramatic epidemiological consequences of this event will be the theme of the next chapter.