The Great Mortality: An Intimate History of the Black Death, the Most Devastating Plague of All Time

by John Kelly

  The siege of Caffa ended with both sides exhausted and decimated by war and disease. In April or May of 1347, as the hills above Caffa turned green under a soft spring sun, the dying Tartar army faded away, while inside the pestilential city, many of the Genoese defenders prepared to flee westward. There are no accounts of life in the besieged port that fateful spring, but we do have images of Berlin in 1945 and Saigon in 1975, enough information to suggest what Caffa’s final days may have looked like. As the death toll mounted, the streets would have filled with feral animals feeding on human remains, drunken soldiers looting and raping, old women dragging corpses through rubble, and burning buildings spewing jets of flame and smoke into the Crimean sky. There would have been swarms of rodents with staggering gaits and a strange bloody froth around their snouts, piles of bodies stacked like cordwood in public squares, and in every eye, a look of wild panic or dull resignation. The scenes in the harbor, the only means of escape in besieged Caffa, would have been especially horrific: surging crowds and sword-wielding guards, children wailing for lost or dead parents, shouting and cursing, everyone pushing toward teeming ships, and beyond the melee, on the departing galleys, prayerful passengers hugging one another under great white sheets of unfurling sail, ignorant that below deck, in dark, sultry holds, hundreds of plague-bearing rats were scratching themselves and sniffing at the cool sea air.

  Caffa was almost certainly not the only eastern port the plague passed through en route to Europe, but for the generation who lived through the Black Death, it would forever be the place where the pestilence originated, and the Genoese, the people who brought the disease to Europe. The chronicler of Este spoke for his contemporaries when he wrote that Genoa’s “accursed galleys [spread the plague] to Constantinople, Messina, Sardinia, Genoa, Marseilles and many other places. . . . The Genoese wrought far more slaughter and cruelty . . . than even the Saracens.”

  Plague is the most famous example of what the Pima Indians of the American Southwest call

  oimmeddam, wandering sickness; and an ancient Indian legend evokes the profound dread

  oimmeddam produced in premodern peoples.

  “Where do you come from?” an Indian asks a tall, black-hatted stranger.

  “I come from far way,” the stranger replies, “from . . . across the Eastern Ocean.”

  “What do you bring?” the Indian asks.

  “I bring death,” the stranger answers. “My breath causes children to wither and die like young plants in the spring snow. I bring destruction. No matter how beautiful a woman, once she has looked at me she becomes as ugly as death. And to men, I bring not death alone, but the destruction of their children and the blighting of their wives. . . . No people who looks upon me is ever the same.”

  Plague is the most successful example of

  oimmeddam in recorded history. Worldwide, the disease has killed an estimated 200 million people, and no outbreak of plague has claimed as many victims or caused as much anguish and sorrow as the Black Death. According to the Foster scale, a kind of Richter scale of human disaster, the medieval plague is the second greatest catastrophe in the human record. Only World War II produced more death, physical destruction, and emotional suffering, says Canadian geographer Harold D. Foster, the scale’s inventor. Harvard historian David Herbert Donald also ranks the Black Death high on a list of history’s worst catastrophes. However, the greatest—if most backhanded—tribute to the plague’s destructiveness comes from the United States Atomic Energy Commission, which used the medieval pestilence to model the consequences of all-out global nuclear war. According to the commission’s

  Disaster and Recovery, a Cold War–era study of thermonuclear conflict, of all recorded human events, the Black Death comes closest to mimicking “nuclear war in its geographical extent, abruptness of onset and scale of casualties.”

  The sheer scope of the medieval plague was extraordinary. In a handful of decades in the early and mid-fourteenth century, the plague bacillus,

  Yersinia pestis, swallowed Eurasia the way a snake swallows a rabbit—whole, virtually in a single sitting. From China in the east to Greenland in the west, from Siberia in the north to India in the south, the plague blighted lives everywhere, including in the ancient societies of the Middle East: Syria, Egypt, Iran, and Iraq. How many people perished in the Black Death is unknown; for Europe, the most widely accepted mortality figure is 33 percent.* In raw numbers that means that between 1347, when the plague arrived in Sicily, and 1352, when it appeared in the plains in front of Moscow, the continent lost twenty-five million of its seventy-five million inhabitants. But in parts of urban Italy, eastern England, and rural France, the loss of human life was far greater, ranging from 40 to 60 percent. The Black Death was particularly cruel to children and to women, who died in greater numbers than men, probably because they spent more time indoors, where the risk of infection was greater, and cruelest of all to pregnant women, who invariably gave birth before dying.

  Contemporaries were stunned by the scale of death; almost overnight, it seemed, one out of every three faces vanished from the human community, and on the broad shires of England, the little villages along the Seine, and the cypress-lined roads of Italy—where the afternoon light resembles “time thinking about itself”—one out of two faces may have disappeared. “Where are our dear friends now?” wrote the poet Francesco Petrarch. “What lightning bolt devoured them? What earthquake toppled them? What tempest drowned them. . . . There was a crowd of us, now we are almost alone.”

  In the Islamic Middle East and North Africa, mortality rates also were in the one-third range. To the Muslim historian Ibn Khaldun, it seemed “as if the voice of existence in the world had called out for oblivion.” In China the presence of chronic war makes it difficult to assess plague mortalities, but between 1200 and 1393 the population of the country fell 50 percent, from about 123 million to 65 million. Today a demographic disaster on the scale of the Black Death would claim 1.9 billion lives.

  The Black Death would be an extraordinary accomplishment for any wandering sickness, but it is an especially extraordinary one for a sickness not even native to humans. Plague is a disease of rodents. People are simply collateral damage, wastage in a titanic global struggle between the plague bacillus

  Yersinia pestis and the world’s rodent population.*

  Y. pestis’s natural prey are turbots, marmots, rats, squirrels, gerbils, prairie dogs, and roughly two hundred other rodent species. For the pathogen to ignite a major outbreak of human disease on the scale of the Black Death, a number of extraordinary things had to have happened. And while we will never know what all of them were, from about 1250 onward, social, economic, and perhaps ecological changes were making large parts of Eurasia an increasingly unhealthy place to live.

  One new risk factor was increased mobility. Along with facilitating international trade, the Mongol unification of the steppe brought merchants, Tartar officials, and armies into proximity with some of the most virulent, and heretofore isolated, plague foci in the world. Rodents (and more to the point, their fleas) that once would have died a lonely, harmless death on a Gobi sand dune or Siberian prairie now could be transported to faraway places by caravans, marching soldiers, and riders of the Mongol express, who could travel up to a hundred miles a day on the featureless, windswept prairies of the northern steppe.

  Environmental upheaval may also have played a role in the origin of the plague. Like a vain old matinee idol,

  Y. pestis is fond of ecological drum rolls. In the mid-sixth century, during the pestilence’s first (documented) visit to Europe, the Plague of Justinian, there were reports of blood-colored rain in Gaul, of a yellow substance “running across the ground like a shower of rain” in Wales, and of a dimming of the sun everywhere throughout Europe and the Middle East. “We marvel to see no shadow on our bodies at noon, to feel the mighty vigor of the sun’s heat wasted into feebleness,” wrote the Roman historian Flavius Cassiodorus.

  Similar, if le
ss flamboyant, accounts of environmental instability appeared in the decades prior to the Black Death. In the West as well as the East, there were reports of volcanic eruptions (Italy), earthquakes (Italy and Austria), major floods (Germany and France), a tidal wave (Cyprus), and swarms of locusts “three German miles” long (Poland). However, since the medieval world viewed natural disasters as portents and expressions of Divine Wrath, these accounts have to be read with caution. Undoubtedly, many of the calamities described by European—and Chinese—chroniclers were invented or exaggerated beyond recognition after the fact to provide the Black Death with a suitably apocalyptic overture.

  That said, tree ring data indicates that the early fourteenth century was one of the most severe periods of environmental stress in the last two thousand years—perhaps due to unusual seismic activity in the world’s oceans. And modern experience shows that ecological upheaval in the form of droughts, floods, and earthquakes can play a role in igniting plague, usually because such events dislodge remote wild rodent communities, the natural home of

  Y. pestis, from their habitats and drive them toward human settlements in search of food and shelter.

  Social and demographic conditions are also risk factors in plague. Like other infectious illnesses, the disease requires a minimum population base of four hundred thousand people to sustain itself. When human numbers fall below that base—or people are dispersed too widely—the chain of infection begins to break down. Sanitary conditions are important, too. A principal vector in human plague, the black rat—

  Rattus rattus—feeds on human refuse and garbage, so the filthier a society’s streets and homes and farms, the larger its plague risk. Since the flea is an even more critical disease vector, personal sanitation matters as well; people who wash rarely are more attractive to an infected flea than those who wash regularly. Humans who live with farm animals are also at greater risk because they are exposed to more rats and fleas; and if a population lives in homes with permeable roofs and walls, the risk is even greater.

  The role of malnutrition in human plague is controversial, though perhaps unjustifiably so. It is true that bacteria, which require many of the same nutrients as humans, have more difficulty reproducing in malnourished hosts. But experience with plague in early-twentieth-century China and India suggests that nutritional status, like sanitation, is a risk factor in the disease, and emerging research suggests that nutrition may also affect susceptibility in another, more subtle way. Recent studies have found that exposure to malnutrition in utero damages the developing immune system, creating a lifelong vulnerability to illness in general.

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  From Caffa to the jungles of Vietnam,* war has also been an important predisposing factor in human plague. War creates human remains and refuse, which attract rats; filthy bodies, which attract fleas; and stresses, which can lower immune system function. Marching soldiers and cavalry also help to make a pestilence more mobile.

  The historical evidence suggests that the existence of only a few of these conditions is not enough to ignite a pandemic, or major outbreak of plague. The Victorian West, for example, was far more densely interconnected and populated than medieval Europe, but when a major wave of plague swept through China and India a century ago, relatively healthy populations, relatively good sanitation and public health standards, and a sturdy physical plant—wood and brick houses—prevented the plague from gaining a toehold in either America or Europe. The disease reached the West, but after causing a few hundred deaths in Oakland, San Francisco, Glasgow, Hamburg, and several other cities, it died out.

  The era that was once called the Dark Ages and is now referred to (less judgmentally, if no more accurately) as the Early Middle Ages also had several conditions associated with plague, including widespread violence, disorder, malnutrition, and filth—if early medieval Europeans washed or changed their clothes more than once or twice a year, it was the best-kept secret in Christendom. However, foreign trade had virtually disappeared, and the rise of hostile new Muslim states in the Middle and Near East put the plague foci of Central Asia and Africa at a further remove from Europe. Also, the early Middle Ages was a period of profound depopulation. In the sixth and seventh centuries a crumbling Roman Europe lost as much as one-half to two-thirds of its population. From Scotland to Poland, the inheritors of a once great civilization lived huddled together like fugitives in forest clearings. Even if, by some fluke,

  Y. pestis had managed to travel to the early medieval West, it would have failed as miserably as it did in the streets of Victorian San Francisco.

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  By contrast, the environment of the fourteenth century was well suited to

  Y. pestis. By modern standards, the population of medieval Europe was relatively low: about 75 million, compared to today’s nearly 400 million. However, compared to the resources available to the population, the continent had become dangerously overcrowded. The years between 1000 and 1250 were a period of great economic and demographic growth in the medieval West, but when the economy began to stall out after 1250, Europe found itself trapped in what historian David Herlihy has called “Malthusian deadlock.” Medieval Europeans were still able to feed, clothe, and house themselves, but because the balance between people and resources had become very tight, just barely. A worsening climate made the margin between life and death even narrower for tens of millions of Europeans. Between 1315 and 1322 the continent was lashed by waves of torrential rain, and by the time the sun came out again in some places 10 to 15 percent of the population had died of starvation. In Italy especially, malnutrition remained widespread and chronic, right until the eve of the plague.

  In the fourteenth century war was almost as much a constant as hunger. Italy, where the papacy and Holy Roman Empire were fighting for ascendancy, had descended into a Hobbesian state of all against all. There were large, small, and in-between-sized wars raging in the papal states around Orvieto, Naples, and Rome. At sea, Italy’s “two torches,” as Petrarch called Genoa and Venice, were locked in an interminable maritime conflict. And almost everywhere up and down the peninsula, roving bands of

  condottieri (mercenaries) were waging fierce little freelance wars. To the north and west, conflict was raging in Scotland, Brittany, Burgundy, Spain, and Germany, and in the ports and plains and cities of northern France the English and French were fighting the first battles of the Hundred Years’ War.

  “The city makes men free,” medieval Germans told one another, but a combination of people, rats, flies, waste, and garbage concentrated inside a few square miles of town wall also made the medieval city a human cesspool. By the early fourteenth century so much filth had collected inside urban Europe that French and Italian cities were naming streets after human waste. In medieval Paris, several street names were inspired by

  merde, the French word for “shit.” There were rue Merdeux, rue Merdelet, rue Merdusson, rue des Merdons, and rue Merdiere—as well as a rue du Pipi. Other Parisian streets took their names from the animals slaughtered on them. There was a Champs-Dolet—roughly translated as “field of suffering and cries”—and l’Echorcheire: “place of flailing.” Every town of any size in Europe had its equivalent of l’Echorcheire: an outdoor slaughterhouse, where butchers in bloodstained clothing cut and chopped and sawed amid discarded body parts and offal and the agonizing moans of dying animals. One irate Londoner complained that the runoff from the local slaughterhouse had made his garden “stinking and putrid,” while another charged that the blood from slain animals flooded nearby streets and lanes, “making a foul corruption and abominable sight to all dwelling near.” In much of medieval Europe, sanitation legislation consisted of an ordinance requiring homeowners to shout, “Look out below!” three times before dumping a full chamber pot into the street.

  The medieval countryside, where 90 percent of the population lived, was an even more dangerous place than the medieval city. Thinly walled, peasant homes were highly permeable, and the rat-to-person ratio tended t
o be very high in rural areas. Urban rat colonies usually divided their attention among several homes on a street, but in the country, not uncommonly, a single peasant family would find itself the target of an entire rodent colony.

  The medieval body was in as shocking a state as the medieval street. Edward III scandalized London when he bathed three times in as many months. Friar Albert, a monk in Boccaccio’s

  Decameron, displays a more typical medieval attitude toward personal hygiene. “I shall do something today that I have not done for a very long time,” the friar announces cheerfully. “I shall undress myself.” When the assassinated Thomas à Becket was stripped naked, an English chronicler reports that vermin “boiled over like water in a simmering cauldron” from his body.