It was an unprecedented disaster. When the Black Death swept west and northwards through Europe in the dark days of 1347-1351, it brought with it unparalleled suffering and death. With the demographic collapse came social, psychological and economic shock as the survivors struggled to comprehend the enormity of what had befallen. Yet it was also a pivotal point in Western history, maintains David Herlihy in The Black Death and the Transformation of the West (Cambridge, HUP 1985). Not only did the Black Death break the Malthusian deadlock that had stifled medieval society but also it set off a series of economic, social, and cultural shifts that changed forever the face of European society. Analyzing medieval accounts of the pestilence, Herlihy challenges traditional plague epidemiology as well as setting out a case for the powerful consequences of the crisis.
Established epidemiology asserts that the Black Death was an outbreak of plague caused by the bacillus Yersinia pestis. Emerging out of the steppes of Mongolia, where it was endemic among wild marmot populations, plague moved west along the trade routes to Kaffa, a trading port on the Black Sea. There, Genoan merchants contracted the disease and, in their flight, brought it west to Constantinople and the Mediterranean. The growth in maritime trade over the previous century enabled the epidemic to spread beyond the Mediterranean northwards, reaching England late in 1348 and eventually circling around to Russia by 1351. William McNeill, analyzing the Black Death in Plagues and People, agrees with this model. Identifying the Black Death as only one of a series of epidemics that have afflicted human populations over the course of the millennia - albeit a particularly destructive one - he maintains that the domination of the Mongols shifted trade routes northwards to the steppes, first establishing the plague locus in Mongolia and then enabling its spread westwards . There, it met a "virgin" population, unused to plague and unable to defend against its ferocity. Herlihy accepts part of this hypothesis, acknowledging the pattern of spread from east to west. However, he remains skeptical that Yersinia pestis was the biological agent that brought the Black Death.
Contemporary accounts of the Black Death certainly mentioned the buboes considered characteristic of bubonic plague. However, Herlihy notes that not all other symptoms thus described fit with an outbreak of Yersinia pestis. The Florentine "Books of the Dead" and the Acta Sanctorum for instance, mention the "plague girdle," a rash of pustules not seen in modern plague. In addition, the sheer speed of the spread of the outbreak would seem to disprove plague. Modern plague, according to both Herlihy and Samuel Cohn, is a slow moving epidemic . It also, Herlihy notes, should be preceded by a great epizootic among an existing rat population. Not only did such a population of gray rats not exist, he avers, but also there was no such epizootic episode. However, in confusing the black rat (Rattus rattus), which carries Yersinia pestis, with the gray rat (R. norvegicus), which cannot, he betrays a misconception about the epidemiology of plague. The absence of current epidemiological evidence either for or against Yersinia pestis further weakens this aspect of the work. Nevertheless, Herlihy concludes that current understanding of the epidemiological cause of the Black Death is inadequate and that modern Yersinia pestis was not the cause. He does acknowledge, however, that it is possible for a mutant strain of Yersinia pestis to have been involved .
Whatever the epidemiological cause of the Black Death, historians have been divided about the role the Black Death played in the vertiginous collapse in population in the fourteenth century. Thomas Malthus argued that high population and low resources created a situation in which a crisis was inevitable. Certainly, populations were high and prices for basic foodstuffs had risen in the first half of the century. However, populations were already beginning the decline before the Black Death. A Malthusian crisis should thus have occurred earlier. Further, even after populations had collapsed in the first wave of pestilence, subsequent plagues continued to rock Europe and demographic recovery did not occur until the late part of the fifteenth century. Unfortunately, Herlihy also downplays the possible consequences of famine and malnutrition on the morbidity and mortality of epidemic disease. This makes what could be a complex and nuanced argument too simplified and general, drawing conclusions that, while not necessarily incorrect, are very broad and lack persuasive power. Herlihy also rejects the Marxist theory that population loss was due to class struggle, in particular the "crisis of feudalism", in which a drop in noble income from rents led to pervasive violence and higher taxes and thus to a population crisis. Herlihy notes that although such arguments might seem reasonable in highly "feudal" regions such as Normandy, they cannot account for population drops in non-feudal regions like Tuscany. Thus rejecting either the theory that the situation in Europe before the Black Death was a Malthusian crisis per se or a Marxist class struggle, he maintains it was rather a Malthusian "deadlock", in which the population struggled by on barely sufficient resources. The Black Death, he avers, was the trigger to break the deadlock and begin a new cycle of growth and development.
European reactions to the Black Death can be divided into two categories. During the plague and in its immediate aftermath, there was a profound sense of shock in all realms of life. In the long term, however, European populations began to adapt to the changes the plague had wrought. Humanity was not helpless and indeed, Herlihy argues that many of the long-term effects of the plague were ultimately positive to human society. Economically, the first epidemic had seen a mass desertion of cities and a concomitant economic breakdown. After the plague had abated, there continued to be a shortage of workers and subsequent waves of plague only made the situation more acute as the productive life of workers shortened. This forced guilds and church institutions to scramble to recruit new blood as can be seen in the Tuscan guild matriculation rates. One consequence was the broadening of the net of recruitment. Pre-plague, most apprentices had come from established guild families. Now, the guilds accepted more outsiders, leading to increased social mobility and the growth of "new men." Unfortunately, it also led to foreshortened and less rigorous training and an associated decline in skills.
An important consequence of the demographic collapse and the lack of labor was "factor substitution:" the substitution of capital and land for labor. Shifting land use from arable to pasture and investing in oxen both reduced the need for labor. Similarly, in urban areas, Herlihy maintains that investment in labor-saving technology occurred to substitute for high labor costs resulting in an "impressive technological achievement" . Unfortunately, as Cohn notes, Herlihy's examples - in particular, Gutenberg's printing press - do not fully support his thesis. Technological advances often occurred before the Black Death or, for those made post-plague did not achieve widespread use until after the population had begun to recover .
Another important change that occurred in the wake of the plague was in the demographic system. Although population in the Middle Ages remains difficult to assess due to lack of records, there appears to have been a shift in importance from "positive" to "preventive" checks. Men would marry later or not at all, leading to a decreased birth rate. This controlled population growth in England, Herlihy argues, led to increased surpluses, increased investment and, ultimately, to the industrial revolution. However, flaws emerge in his argument. Admitting to the "invisibility" of the poorer classes, he focuses upon the elites. Ignoring the importance of the masses appears to directly contradict McNeill's argument that overall English population growth and the availability of labor actually aided industrial development . Some engagement with such arguments would surely have been apposite here. In addition, Herlihy again downplays the importance of positive checks such as disease or famine on populations, as argued by McNeill. He also ignores such pre-plague preventive checks on elite populations as monasticism and other celibate lifestyles or the role of chivalry and its concepts of brotherhoods of unmarried knights. This all results in a somewhat simplified narrative of change.
Short-term shock and long-term change not only affected economics and demographics but also social and cultural balances in late Medieval Europe. In the short term, Herlihy notes a focus upon death not as a release, surrounded by comforting and restorative ritual but as a "ravishing monster" . This is reflected in the art and literature of the time. Drawing upon Florentine accounts of the pestilence, he also notes a breakdown in leadership, an increasing fear of minorities and strangers - that manifested as persecution of Jews and lepers - and a collapse in confidence in the church leadership, which resulted in the flagellant movement. Regrettably, his reliance upon a limited number of Tuscan sources proves a particular problem here and his analysis leads to as many questions as answers. What, for example, was the true extent of the penitent movements Herlihy characterizes as "massive?"  Why was persecution of Jews limited in geographical scope? How did contemporaneous accounts portray the flagellant movements? Lack of evidence and a broad generalization from evidence of a limited geographical scope once again undermine the force of Herlihy's case.
Similarly, problems of evidence occur in Herlihy's discussion of longer-term repercussions. Although the growth in geographical scope and extent of medieval universities appears well-supported, the dating of a growth in interest in the classics to the post-plague era is more troublesome . Correspondingly, the rejection of Galenic theory in favor of more practical medicine appears to mirror Cohn's more extensive work on the subject, yet Herlihy's assertion that the debate over the role of contagion ended with the Black Death contradicts the evidence presented more forcefully by McNeill that the debate remained unresolved until the late nineteenth century . Finally, his assertion that the Christian character of pre-plague Europe cannot be known but analysis of naming records suggests a lack of religiosity seems particularly peculiar. Herlihy passes over earlier evidence of Christian piety such as The Book of Sainte Foy - which points in particular to a "cult of saints" in the tenth not just the fourteenth century - as well as other chronicles, accounts of pilgrimages, donation records and the rise of the mendicant orders to conclude that only with the Black Death did religious feeling intensify. A more apt reading of the evidence might suggest that the Black Death was only one of a number of factors that shifted Christianity from a more institutional, ritualized model to one that was more personal and spiritual.
Certainly, the Black Death was a watershed point in medieval history. The society that emerged in the second half of the fourteenth century was markedly different from that of a century before and many of the changes can be attributed in great part to the impact of the plague and the accompanying demographic collapse. Indeed, many of Herlihy's speculations appear borne out by the analysis of other historians. However, the limited range of the sources that Herlihy draws upon, especially the focus upon Tuscan records and accounts to the detriment of those from Northern Europe, and the generalization of his conclusions to all of Europe from these sources, diminishes the force of his argument. Furthermore, in ignoring other sources and by not entering into a dialogue with the conclusions of other historians, Herlihy loses a great deal of complexity and nuance. His The Black Death and the Transformation of the West, while a useful starting point for discussion of the Black Death, is thus less valuable than it might have been.
Notes1. William McNeill, Plagues and Peoples (New York: Anchor, 1977) 175-6.