The Egyptian land bridge, separating the Red Sea and southern oceans from Mediterranean waters, was obviously a significant barrier to the movement of ships’ rats and their fleas. Hence an infection familiar enough for centuries among rats, fleas, and people of Indian Ocean ports could have dramatic and unparalleled effects when, by some accident, it surmounted the usual barrier and burst in upon virgin populations of the Mediterranean among whom acquired resistances to the disease and conventional means for coping with it were entirely lacking. A chronic risk to human life in India and Africa (for which in all likelihood suitable customary responses had been devised by folk wisdom and practical experience) could therefore manifest itself in Justinian’s world as a lethal disease of catastrophic proportions.
Historic evidence, indeed, suggests that the plagues of the sixth and seventh centuries had an importance for Mediterranean peoples fully analogous to that of the more famous Black Death of the fourteenth century. The disease certainly provoked an initial die-off of a large proportion of the urban dwellers in affected regions, and the over-all diminution of population took centuries to repair. Precision is, of course, quite impossible; but Procopius reports that at the peak of its first visitation the plague killed 10,000 persons daily in Constantinople, where it raged for four months.72
As in the case of the earlier great pestilences of 165–180 and of 251–266, the political effects of this plague were far-reaching. Indeed, the failure of Justinian’s efforts to restore imperial unity to the Mediterranean can be attributed in good part to the diminution of imperial resources stemming from the plague. Equally, the failure of Roman and Persian forces to offer more than token resistance to the Moslem armies that swarmed out of Arabia so suddenly in 634 becomes easier to understand in the light of the demographic disasters that repeatedly visited the Mediterranean coastlands from 542 onward, and accompanied the Moslems in the first critical stages of their imperial expansion.73 More generally, the perceptible shift away from the Mediterranean as the preeminent center of European civilization and the increase in importance of more northerly lands—a shift Henri Pirenne noticed and made famous years ago—was powerfully assisted by the long series of plagues, which confined their ravages almost entirely to territories within easy reach of Mediterranean ports.74
To be sure, epidemics were not absent from northern Europe in these centuries. A severe disease raged in the British Isles after the Synod of Whitby (664) had brought together churchmen from Ireland, Wales, and England, for instance; though whether it was plague, smallpox, measles, influenza, or something else is hotly disputed.75 This was the most important but by no means the only such visitation; indeed, Anglo-Saxon records mention no fewer than forty-nine outbreaks of epidemic between A.D. 526 and 1087.76 Many of these were relatively minor; and indeed, a pattern of increasing frequency but declining virulence of infectious disease is exactly what a population learning to live with a new infection experiences as the accommodation between hosts and parasites moves toward a more stable, chronic state.
What is not clear is whether the ravages of disease were heavier in urbanized Mediterranean lands than in the rural Germanic and Slavic portions of Europe. Some diseases needed urban crowding (or equivalent military concentrations of personnel into armies and fleeing hordes) to attain epidemic intensity. This was generally the case for diseases communicated through drinking water—typhoid, dysentery, and the like. Some, like the plague, seem to have been confined to Mediterranean lands, simply because Indian black rats had not yet established themselves in Atlantic seaports. But other diseases, including both measles and smallpox, were capable of spreading far and wide amid rural communities; and previous isolation tended always to make the arrival of such an infection more lethal among rural folk than was likely in disease-experienced cities. Thus a priori considerations work in opposite directions, and one must remain content with uncertainty as to whether urbanized Mediterranean populations suffered more or less from epidemic diseases than rural northern peoples did.
What is certain is this: until after A.D. 900 the Germanic and Slavic peoples of Europe did not suffer anything like the macroparasitic drain on their resources that the continued existence of the Roman imperial state and of Mediterranean urban populations imposed on the peasantries of the South. Differential population growth, which does indeed seem to have favored the more northerly peoples, probably reflected this fact as much as any microparasitic advantage that may have arisen from the rural and dispersed patterns of settlement characteristic of the North. The chief evidence for population growth in the North between the fifth and eighth centuries A.D. is the colonization of the Balkan peninsula by Slavs and of Britain, together with the Rhine and Danube frontier lands, by Germanic settlers. Behind the Viking raids, 800–1000, must also lie a substantial swarming of population in remote Scandinavian fjords and coastlands.
To be sure, factors other than the balance between micro- and macroparasitism affected Europe’s population. In particular, food production increased in northwestern Europe between the fifth and eleventh centuries, thanks to important improvements in agricultural methods resulting from the spread of moldboard plows. This in turn sustained the beginnings of what in some essentials was a new style of civilization—organized states, hierarchical churches, and expanded movement of goods by sea and land, whether for raiding or trading—all brought about intensified contacts with the Mediterranean lands to the south. Within limits set by climatic gradients and population densities, therefore, the tendency clearly was for European populations as a whole to become sharers in a single disease pool, even in such formerly remote lands as Scandinavia and Ireland.
As this process worked itself out, diseases that on their initial appearance in Europe had been highly lethal, settled toward endemicity, at least in those places where sufficiently dense populations existed to sustain a chain of infection indefinitely. In fringe areas, where population was not dense enough to sustain a stable pattern of endemic infection, demographically costly epidemics continued to break out from time to time. Such pestilences sallied forth from regions of endemicity along the routes of trade and communication connecting scattered populations with the urban centers. This situation persisted in rural and remote parts, especially islands, until the nineteenth century.77
As encounters with such epidemics increased, however, death tolls decreased. Shortened periods of time between successive exposures meant an increase in the proportion of persons with effective immunities created by earlier disease invasions of the community in question. When a given disease returned at intervals of a decade or so, only those who had survived exposure to that particular infection could have children. This quickly created human populations with heightened resistances. The upshot, therefore, was relatively rapid evolution toward a fairly stable pattern of co-existence between host and parasite.
An infectious disease which immunizes those who survive, and which returns to a given community at intervals of five to ten years, automatically becomes a childhood disease. And since children, especially small children, are comparatively easy to replace, infectious disease that affects only the young has a much lighter demographic impact on exposed communities than is the case when a disease strikes a virgin community, so that old and young die indiscriminately. This process of epidemiological adjustment was energetically under way in Europe as a whole during the so-called Dark Ages. As a result, the crippling demographic consequences of exposure to unfamiliar diseases disappeared within a few centuries.
In western Europe adjustment to intensified microparasitism seems to have taken place long before containment of excessive macroparasitism proved feasible. It was only after about A.D. 950 that a class of knights, suitably armed and trained, and supported locally by peasant villages, became numerous enough on the ground and formidable enough in the field to repel Viking sea raiders from the most fertile regions of northwestern Europe. From that time forward, despite continued local disorders and sporadic renewal of depredation, th
e population of that part of the continent entered a new period of dramatic growth.
By that time, the biological as well as the political and psychological consequences of the interpenetration of civilized disease pools that commenced in the second century A.D. had been fully absorbed; and western Europe was in a position to cash in on technical and institutional innovations that had been propagated throughout Latin Christendom during the troubled centuries when that part of the earth came fully and finally into the circle of civilized lands.
No comparably circumstantial history of gradual accommodation to new diseases can be written for any other part of the world. It is probable that if scholars with appropriate linguistic skills were to comb Chinese sources for information about diseases in the Far East, similar patterns of initial disaster and subsequent epidemiological adjustment to new diseases would become apparent. Chinese medical literature is ancient and abundant; and references to unusual outbreaks of disease occur frequently in official dynastic histories, as well as in other sorts of records. But there are difficult problems of interpretation, and the scholars who have paid any attention at all to disease in ancient China and Japan approached the problem without asking the questions that are most important for this inquiry. Until expert and careful work has been done, therefore, answers which may be buried in the vast array of Chinese and Japanese texts remain inaccessible.
A few points do deserve our notice nonetheless. For China two compilations of recorded epidemics exist: one the work of a scholar of the Sung Dynasty (960–1279) named Ssu-ma Kuang, and a second compiled in 1726 as part of an imperial encyclopedia. The published versions of these two lists contain inaccuracies of transcription and calendrical translation; but it is possible to conflate the two and correct at least some of their errors by checking the sources they cite. The result is the list of recorded epidemics in China reproduced in the Appendix.78
By charting epidemic outbreaks thus recorded on a time line, two major clusters appear in the early Christian centuries, and two particularly severe die-offs stand out: one in A.D. 161–62, the second in 310–12. According to the list, in 162 a pestilence broke out in the Chinese army serving on the northwestern frontier against the nomads. Three or four out of ten men died. In 310–12, another great pestilence, preceded by locusts and famine, left only one or two out of a hundred persons alive in the northwestern provinces of China; and this was followed ten years later, in 322, by another epidemic in which two or three out of ten died over a wider region of the country.
Obviously the first of these might and the second must—if the recorded statistics are even approximately correct—represent the arrival in China of some hitherto unknown infection, else such rates of mortality could not have occurred. In the second case, a disease involving rash and fever may well have been responsible, since the earliest description of such an illness traceable in Chinese medical writing comes from the hand of a doctor who lived A.D. 281–361, named Ho Kung. The relevant passage of his book has been translated as follows:
Recently there have been persons suffering from epidemic sores which attack the head, face and trunk. In a short time, these sores spread all over the body. They have the appearance of hot boils containing some white matter. While some of these pustules are drying up a fresh crop appears. If not treated early the patients usually die. Those who recover are disfigured by purplish scars which do not fade until after a year.79
This seems like a clear description of smallpox (or measles), but there are difficulties, since the passage continues:
The people say that in the fourth year of Yung-hui (A.D. 653) this pox spread from west to east and spread far into the seas. If the people boiled edible mallows, mixed them with garlic and ate the concoction, the epidemic would stop. If when first contracting the disease one ate the concoction with a small amount of rice to help it down, this too would effect a cure. Because the epidemic was introduced in the time of Chien-wu (A.D. 317 or, alternatively, A.D. 25–55), when Chinese armies attacked the barbarians at Nan-yang, it was given the name of “Barbarian pox.”80
Reference to an event three hundred years after Ho Kung’s lifetime certainly confuses the question of when this description of smallpox was first composed. Inasmuch as it was a common practice for Chinese scholars to attribute their own words to ancients, since antiquity made a text more respectable, one cannot be sure that Ho Kung wrote this part of the text ascribed to him, or that smallpox came into China in the early fourth century A.D. Nevertheless, the likelihood remains fairly high.
What one can conclude, even from this fragmentary and imperfect data, is that some time between A.D. 37 and A.D. 653 diseases like smallpox and measles arrived in China. Coming overland from the northwest, they acted like new infections, breaking in upon a virgin population. Demographic consequences must have been similar to those the Roman world was experiencing at the same time.
As for bubonic plague, the earliest Chinese description of this disease dates from A.D. 610. In 642 another writer again mentioned it and observed, significantly, that plague was common in Kwangtung (i.e., the province in which Canton is located) but rare in the interior provinces.81 On the strength of these references it seems reasonable to believe that bubonic plague came to China via the seaways, arriving early in the seventh century, i.e., about two generations after the disease had penetrated the Mediterranean in 542.
In China as in the Mediterranean, outbreaks of bubonic plague must have depended on the prior dispersal of the black rat and its fleas. Rats may have taken a few centuries to work their way into the local life balances in sufficient numbers to create the conditions for really large-scale outbreaks of human plague. At any rate, a series of epidemics broke out in the coastal provinces of China, beginning in the year 762, when “more than half the population of Shantung province died,” and recurred from time to time until 806, when the same high rate of mortality was reported for Chekiang province.82
On the basis of this imperfect evidence, then, the disease history of China in the early Christian centuries seems to have resembled that of the Mediterranean lands, inasmuch as new and lethal infections probably arrived in China, traveling both overland and across the sea. Moreover, there is sufficient reason to believe that Chinese population dropped sharply from the total of about 58.5 million recorded in A.D. 2. As in the Mediterranean lands, decay of population brought with it disruption of administration, and the records that survive are both fragmentary and unreliable. When another more or less dependable census becomes available for China, in A.D. 742, the number of hearths recorded was about 8.9 million, whereas in A.D. 2 a total of 12.3 million hearths had been registered. In between, various fragmentary statistical returns suggest far more drastic depopulation of certain parts of China, especially in the South where comparative security from raiding nomads was perhaps more than counterbalanced by the heavier disease risk to which peasants pursuing a Chinese style of cultivation were liable. By the middle of the fifth century, for instance, the region around Nanking on the middle Yangtze registered only one fifth as many hearths as in the year 140. Decay in the North, while substantial, was proportionately not so great.83
There are other and well-known parallels between Roman and Chinese history in these centuries. The fabric of imperial administration broke down in China with the end of the Han Dynasty in A.D. 220. Invasions from the steppes and political fragmentation ensued, and by the fourth century as many as sixteen rival states competed for control of China’s northern provinces. Maximal political fragmentation coincided almost exactly with the putative arrival of smallpox and/or measles in China in A.D. 317, and if mortality was anything near the severity recorded by Ssu-ma Kuang (“one or two out of a hundred survived”) it is easy to see why. The figure of 2.5 million hearths in A.D. 370 as against 4.9 million hearths for the same region of northern China in A.D. 140 may indeed be more credible than scholars who have not bethought themselves of the disease variable are inclined to believe.84
As of A.D.
589 China achieved political unification once again, whereas Justinian’s parallel effort (reigned 518–65) to re-establish a Roman empire of the Mediterranean failed. One difference was that Justinian’s empire was weakened by repeated exposure to plague from 542 onward, whereas comparably severe plague attacks do not seem to have occurred in China until after 762, and then they affected only coastal provinces. Nevertheless, the breakup of effective central authority in China subsequent to a great military revolt of A.D. 755 did coincide rather closely with these outbreaks of plague. Disease as crippling to a vulnerable population as bubonic plague normally is may well have made it impossible for the imperial authorities to gather sufficient resources from the coastal provinces (which were unaffected by the revolt) to be able to put down the rebellion. Instead, the emperor called upon the help of nomad Uighur armies. As victors, the Turkish-speaking Uighurs were in a position to dictate terms, and speedily siphoned off a considerable part of the imperial resources for their own uses.
Religious history also offers another striking parallel between Rome and China. The Buddhist faith began to penetrate the Han empire in the first century A.D., and soon won converts in high places. Its period of official dominance in court circles extended from the third to the ninth centuries A.D. This obviously parallels the successes that came to Christianity in the Roman empire during the same period. Like Christianity, Buddhism explained suffering. In the forms that established themselves in China, Buddhism offered the same sort of comfort to bereaved survivors and victims of violence or of disease as Christian faith did in the Roman world. Buddhism of course originated in India, where disease incidence was probably always very high as compared with civilizations based in cooler climates; Christianity, too, took shape in the urban environments of Jerusalem, Antioch, and Alexandria where the incidence of infectious disease was certainly very high as compared to conditions in cooler and less crowded places. From their inception, therefore, both faiths had to deal with sudden death by disease as one of the conspicuous facts of human life. Consequently, it is not altogether surprising that both religions taught that death was a release from pain, and a blessed avenue of entry upon a delightful afterlife where loved ones would be reunited, and earthly injustices and pains amply compensated for.
Plagues and Peoples Page 15
