The Black Death, and plague in general, aren't what they used to be. The advances made in knowledge of these matters over the past two decades have utterly transformed the old narrative, and the contributors to this volume, themselves monitors of and contributors to this transformation, have put together the most comprehensive survey of where all facets of plague study stand presently and appear to be headed.
The volume in question is the first of a new annual publication, The Medieval Globe, of which each number will be devoted to a single theme. Its founding executive editor, Carol Symes, sees it "as dedicated to exploring varieties of connectivity, communication, and exchange...during the millennium or so prior to 1500" (2). More concretely, these varieties could embrace "the means by which peoples, things, and ideas came into contact with one another; the deep roots of global developments; and the ways that the perception of ‘the medieval' have been (and are) created around the world" (4).
One would be hard pressed to find a topic better suited to meet these editorial criteria than the history of one of our planet's most feared if not actually deadliest infectious diseases, namely Yersinia pestis, aka plague. That plague qualifies as a global disease in modern times is evident from the story of how, after a half-century trek across the Yunnan Province in southern China, it arrived in the spring of 1894 at Hong Kong, whence steamships facilitated its spread to all except the polar continents within less than a decade. But the Black Death? In the 14th century?
The guest editor for this initial volume, Monica H. Green, is for her part well along on producing a global history of no fewer than eight infectious diseases: cholera, HIV-AIDS, leprosy, malaria, smallpox, syphilis, tuberculosis, and Yersinia pestis; she is thus able to introduce comparative observations where these can shed light. In her magisterial introductory essay Green demonstrates persuasively just what makes the Black Death global, starting with the ancient DNA (aDNA) studies of the late 1990s, which over the next decade established that the historically documented pandemics of the 6th-8th and 14th-19th centuries were of the same disease, i.e. Yersinia pestis, as that identified independently by Yersin and Kitasato using the then new laboratory methods during the 1894 epidemic at Hong Kong. Green shows mastery of the phylogenetic studies that have established the pathogen's evolutionary history back to its origins, not just in time but in space, specifically to the Tibetan-Quinghai plateau (now claimed by China), which at its highest points reaches over 4,000 meters. This discovery raises in turn the question of how it got to the Middle Eastern, European, and North African areas that surround the Mediterranean, where it so devastated human populations. The complexity of the matter is only hinted at by the realization that the bacterium had to pass from elevations of a few thousand meters down to sea level, moving across many animal species, both arthropod vectors (fleas), and their mammalian hosts (rodents of many different species) and thus also across several different climatic zones. The role of homo sapiens in this puzzle must of course be included as well.
Green does not settle for assuming that the transfer to the Mediterranean Basin took place via a direct East-to-West overland trajectory, for she also explores a possible southern route through India and thence westward across the Indian Ocean to the Arabian Peninsula and East Africa. On the basis of mainly written sources, which include much information on trade and sailing routes, this qualifies as another plausible itinerary for the sixth-century Drang nach Westen. There is less such evidence for the 14th-century drive but this need not rule it out completely. Phylogenetic research on strains of plague found in recent decades in East and Central Africa point to a variant that emerged only between the 14th and 17th centuries. While there is little evidence of thriving urban centers and trade routes in sub-Saharan Africa in those earlier centuries, just such centers and routes were indeed well developed by the 14th century. The lone type of evidence that at present suggests a plausible way to coordinate a Central/Southern African plague hypothesis is archeological, namely creditable indications of depopulation based on the abandonment of previously lively urban centers--earthwork settlements in present-day Ghana--during the 14th century.
Did the Yersinia pestis travel eastwards? There is no proof at present that it reached China before the eighteenth century--or anywhere in East Asia--and while some sinologists insist that there was no plague earlier in China, others are trying to figure out whether, and if so how, it might have gotten there. Green makes mention of these possibilities as well, although mainly directs the reader to the deftly crafted hypothesis by Robert Hymes later in the volume, where he explores how an avenue for the passage of Yersinia pestis from the high plains into northern China could have opened up in the 13th century. The occasion was the lengthy and destructive conquest of the Xia state in northern China carried out by the Mongols under Genghis Kahn between 1205 and 1227, and the avenue in fact took the Mongols' army through the northern edge of the Quinghai Plateau. The invaders lost large numbers of men to disease and Chinese sources began recording new deadly epidemics exactly in the years of this long, drawn-out conquest. Here, then, a scholar is proposing, as a hypothesis but on the basis of a formidable array of corroborating evidence, that plague entered a territory where no one has ever previously come close to proving that it had been present, and that this same pandemic began a full century earlier than we have been accustomed to believe. All in all, then, the reach of Black-Death historical study needs to extend its chronology and, as for geography, embrace Africa, sub-Saharan as well as northern, along with the full length of Eurasia.
We turn to areas where the presence of past epidemics of plague is not doubted: Egypt, the Ottoman Empire, and Western Europe. While environmental studies are essential for our understanding of the conditions needed to support an environment hospitable to vectors, Stuart Borsch reverses the pattern by studying a case in which massive depopulation due to plague in Egypt led to an environmental change that in turn devastated the country's economy. Long before the 14th century the Egyptians had found ways to expand their use of both the Nile and the desert by constructing--with massive human labor--canals to draw water away from the river at flood time and to store it in huge basins built of circular dykes. Each autumn, though, this infrastructure took a beating during the annual floods and so required repairs that called, again, for many thousands of workers, specifically for dredging the canals and rebuilding collapsed sections of the dykes. Beyond the initial onslaught of plague in 1347-1350 with its appalling mortality, each of the many return visits took a share of the labor force, so that by the late 15th century in some places the flood waters drowned land, villages, people, and farm animals, while in others once-rich fields reverted to parched earth. These were the effects of past deaths amidst the labor force and causes of yet more deaths. The dramatic fall by 60% of the country's agrarian output by the early 1500s left little chance for economic recovery, and this downward spiral carried on into the 19th century.
Nükhet Varlik presents here a most welcome correction to the prevailing (mostly Eurocentric) narrative of plague history in her study of the Ottoman experience of the disease. She tells of the notion of the "Ottoman laboratory", based upon the fact that in the 19th century plague had vanished from Western Europe and yet persisted in Ottoman territories, so that the latter served the needs of European medical research as a convenient locus for direct observation. This convenience did nothing to cancel out another Euro-notion that held that "the East" was responsible for plague in the first place and for sending it westward. Particularly arresting in these pages are the author's reflections upon how the disease could have persisted as long as it did, considering that Istanbul alone recorded over 230 outbreaks between 1347 and 1800. In between epidemics plague is well known to endure for very long periods of time in an enzootic state, but usually in areas remote from human communities. However, Varlik's research suggests the possibility that urban areas with large commensal rodent populations could well have served as temporary reservoirs of plague.
Ann Carmichael's essay "Plague Persistence in Western Europe: A Hypothesis" centers, as her title makes clear, on this very problem of persistence. In a brilliant series of observations about topography, climate, and rodent populations of Alpine Europe, and about how connected by roads and rivers that that area is to the thriving commercial centers of Lombardy, Carmichael constructs a hypothesis by which one can (1) perceive a large area in the alpine regions sparsely peopled but abundantly inhabited by various rodents, most especially marmots; (2) note that the travel routes that go over the few mountain passes served principally long-range travelers such as merchants, soldiers, emissaries, pilgrims, and others; and (3) understand how a land-locked city like Milan could be subjected to a plague epidemic coming not from coastal cities but from its own hinterland. What is at stake here is an explanation of how Milan and some of the other cities of Lombardy escaped the 1347-1350 onslaught but suffered the equally horrific (for them) "second pestilence" of 1359-1363. The use of this hypothesis goes beyond understanding that one epidemic. Indeed, Carmichael is right to call for much greater attention to the outbreaks that continued to recur right through the early modern period, when practically all the cities of northern Italy lost a third or more of their inhabitants five or six times.
Still in Europe but turning to archeology, the editor has wisely included a study by Catalan scholars about newly found material remains that confirm historical documentation dating from 1348. Among the earliest records of the scapegoating of Jews for having caused the epidemic are those from Aragon. These report the deaths of 20 Jews in Barcelona, 18 in the city of Cervera (c. 50 miles northwest of Barcelona), and 300 in the small market town of Tàrrega (c. 10 miles further to the West) known for its many artisans including goldsmiths and for its sizeable community of Jews. Archeologists recently discovered the Jewish cemetery there, including six mass graves, dating from 1348. These contained the remains, mostly marked by violent trauma, of 69 individuals, including both males and females, ranging in age from infants to the elderly. While mass graves were not normal in Jewish cemeteries, the bodies were all laid out in orderly fashion, heads to the West, feet to the East. The investigators surmise that Jewish survivors had buried the victims. Written testimonies to pogroms related to plague epidemics are legion, but this dig is the first of its kind.
Now onto bioarcheology and bioanthropology with the essay by Sharon De Witte, whose task was to show what the skeletal remains of some 14th-century plague victims can reveal, not just of their age and sex but medical history as well. Her starting point is to cite contemporary chroniclers who, in her words, "suggest that the Black Death killed indiscriminately, irrespective of age or sex"(101). The remains she used come from the East Smithfield Cemetery, which was started outside the walls of London in 1348-1349 because of the vastly increased mortality rates in the city's population at the moment. As I am not competent to discuss the merits of various methods for determining the pre-existing medical conditions of plague victims, I shall go directly to the author's conclusions. The prized items in this research were skeletal markers of physiological stress such as malnutrition or infectious disease, some of which indicate that the stress was experienced in childhood, otherwise at any time during the individual's life until shortly before death. Hence, "people…who developed stress markers...were...more likely to die during the Black Death compared to their peers who lacked the stress markers"(114). This is an important finding, although it is noteworthy that the author does not assign these markers to a particular cause. Still, there remains for me a question about Yersinia's indiscriminant nature. Is it not the case that, in the absence of anti-biotics, primary pneumonic plague ignores a subject's medical history because it is virtually 100% fatal?
While we have gained this insight into why plague killed some of the people it invaded, Fabian Crespo and Matthew B. Loren ask whether persons who survived Yersinia pestis already had or acquired or retained and/or passed along immunity to it. They state their hypothesis succinctly: "A more comprehensive and accurate reconstruction of medieval demography will be the only way to reconstruct the IC (immune competence, i.e., the individual immune system's responsiveness) of individuals and populations in this era" (251). I appreciate the question and am loathe to discourage anyone from seeking an answer, but, based on the difficulties of knowing much of anything about individuals in the period to which you refer, I worry about the phrase "only way", and hope that cemeteries will reveal also to you still more of the secrets they've been keeping.
Michelle Ziegler is well placed to write of the future of plague because her work involves thinking about and preparing for it. A biologist who works in a DNA diagnostics lab and who writes a blog, Contagions, which aims at bridging biomedicine and medical history, she is also trained in biosecurity and disaster preparedness. Following a thorough survey of the status of Yersinia pestis in the world at present, she makes a strong case for better reporting of infectious disease epidemics, better control of air travel and borders against bioterrorism and innocent transmission of disease, more attention to the dangers of anti-biotic resistance and of a recrudescence of pneumonic plague.
Reviewers frequently close by saying that the book under review shall long remain the standard work in the field. To invoke that cliché here is out of the question. The authors of these essays know well that the very ground upon which they are working is constantly shifting. Since this book was published scientific articles affecting virtually every theme mentioned in it have been appearing. The results of gathering so many types of expertise published here make the best case for encouraging yet more interdisciplinary literacy and communication.