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

by John Kelly

  Arguably, medieval Europe’s reigning religious and medical orthodoxies also created a vulnerability to plague by promoting a public health program based on clothing the wicked, inhaling fragrances, and prayer. The educated classes, influenced by the theories of a former sports physician and Roman celebrity doctor named Galen, believed that the pestilence arose from miasmas—dense clouds of infected air. “Corrupted air, when breathed in, necessarily penetrates to the heart and corrupts the substance of the spirit there,” warned the Paris medical faculty, the most eminent medical body of the day. The “prince of physicians,” the Italian Gentile da Foligno, recommended the inhalation of herbs as an antidote for “corrupt” air.

  To the Church and common folk, the plague was seen as a form of divine retribution for human wickedness. Henry Knighton, an English monk who hovers over the Black Death like a cackling Shakespearean witch, exemplifies this school of thinking. Knighton believed that God smote a third or more of Europe because medieval England’s most glamorous young women were becoming tournament groupies. “Whenever and wherever tournaments were held,” Knighton wrote a few decades after the Black Death, “a troupe of ladies would turn up dressed in a variety of male clothing . . . and mounted on chargers. There were sometimes as many as forty or fifty of them, representing the showiest and most beautiful, though not most virtuous, women of the realm. . . . [They] wore thick belts studded with gold and silver slung across their hips, below the navel . . . and were deaf to the demands of modesty. But God, present in these things, as in everything, supplied a marvelous remedy”—plague.

  Plague is among the slowest moving of wandering sicknesses. New strains of influenza can leap around the world in a year or two, but

  Y. pestis, like the AIDS virus, is tied to a complicated chain of infection that can take decades to unfold. The principal vector in the disease is not the rodent, the animal most often associated with it, but the rodent flea. When an infected host dies, the flea leaps to a new host, transferring the plague bacillus,

  Y. pestis, to the host by way of a skin bite. Sometimes humans are infected directly by one of the many flea species that prey on wild rodents, such as squirrels, prairie dogs, and marmots; however, most often the agent of infection in human plague is the more familiar black rat flea,

  Xenopsylla cheopis.

  In human plague, the chain of infection can take several forms. For example, an ecological disaster, which destroys the food supply, or a dramatic spike in the rodent population, which puts tremendous pressure on it, may drive a colony of infected animals toward a human settlement, where members of the colony exchange fleas with domestic rats. Another possible scenario that may have relevance to the Black Death is that a group of travelers stumble into a wild rodent community in the midst of a plague outbreak; infected rodents—or their fleas—infiltrate the travelers’ saddlebags and carts, and when the group arrives in the next town or village, the hitchhikers leap from their hiding place and spread the disease to the domestic rodent population. The next-to-last stage in the sequence is the involvement of

  X. cheopis, the rat flea, which becomes a disease vector because, in one way or another, its rat hosts have become infected by wild rodent fleas.

  The jump of plague into man is driven by

  X. cheopis’s desperation. It does not particularly like human blood, but as plague kills off the local domestic rat community, the flea’s only alternatives are starvation or

  Homo sapiens. Once embedded in a human population, the rat flea becomes a very efficient disease vector.

  X. cheopis can survive up to six weeks without a host—long enough to travel hundreds of miles in grain or cloth shipments. It is also an extremely aggressive insect. It has been known to stick its mouth parts into the skin of a living caterpillar and suck out the caterpillar’s bodily fluids and innards. However,

  X. cheopis’s greatest attribute as a disease vector lies in the vagaries of its digestive system.

  In an uninfected rat flea, blood from a skin bite flows directly to the stomach, satiating hunger. In an infected flea, plague bacilli build up in the foregut, producing a blockage; this enhances the insect’s ability to spread infection in two ways. First, because no nutrients are reaching the stomach,

  X. cheopis, chronically hungry, bites constantly; and second, as undigested blood builds up in the foregut, the flea becomes a living hypodermic needle. Every time it bites, it gags on the undigested blood, now tainted with plague bacilli, and vomits it into the new bite.

  The way to get from the digestive problems of a minor insect to 25 million to 30 million dead in Europe, a third of the Middle East wiped out, and China “depopulated,” is by multiplying. Normally a rodent only carries a half dozen or so fleas, but in the midst of an epizootic, when hosts become rare, surviving rodents often become the equivalent of flea towns, carrying a hundred to two hundred insects—and sometimes flea cities. Researchers counted nine hundred infected fleas on one unfortunate ground squirrel in Colorado.

  Three forms of plague prey on humans.

  Bubonic plague, the most common form, is transmitted by a flea bite and has a two- to six-day incubation period. “Behold, the swelling, the warning signs sent by the Lord,” wrote a contemporary, of the Black Death’s most characteristic symptom, the egg-shaped bubo. Medieval chroniclers frequently described the bubo as tumorlike, and the analogy is an apt one. Like malignant cancer cells, once inside the body, plague bacilli multiply with an aggressive wildness. Typically, the site of the flea bite determines the site of the

  gavocciolo, as contemporaries called the bubo. Bacilli from leg and ankle bites produce buboes in the abdominal region or thigh; upper-body bites, buboes under the arms or on the neck. Exquisitely sensitive to pressure,

  gavocciolo often create odd deformations in their victims. Thus, a neck bubo may produce a head permanently cocked in the opposite direction, a thigh bubo a hopping limp, an underarm bubo an outstretched or raised arm. Buboes are also oddly noisy creatures. Human plague speaks to its victims in the strange gurgling tongue of the bubo.

  According to the chroniclers, three other symptoms were also quite common in the bubonic plague of the Black Death. One were

  petechiae. These bruiselike purplish splotches often appeared on the chest, back, or neck, and were also known as “God’s tokens” because their appearance meant the victim had a fatal case of plague. Legend has it that the “tokens” were the inspiration for a Black Death–era nursery rhyme still sung today:

  Ring around the rosie, pocket full of posies

  Ashes, ashes [the hemorrhages], we all fall down.*

  Malodorousness was another frequent symptom of historic bubonic plague. Victims not only looked as if they were about to die, according to many Black Death chroniclers, they often smelled as if they were. After visiting a plague-stricken friend, one man wrote, “The stench [of] sweat, excrement, spittle, [and] breath [was] overpowering.” A number of contemporary accounts also suggest that the medieval plague disrupted the nervous system. There are reports of delirious, agitated victims shouting madly from open windows or walking around half-naked or falling into a stupor.

  Oddly, these last three symptoms are uncommon in modern bubonic plague. Dr. Kenneth Gage, chief of the Plague Division at the U.S. Centers for Disease Control, has encountered “God’s tokens” in his fieldwork, but so infrequently that, when asked if he had ever seen a plague victim with hemorrhagic bruises, he had to stop and think for a moment. While the CDC official has encountered many cases of malodorousness, he describes the foul odor as a by-product of poor nursing care—the plague victim was not being changed or bathed regularly, or lived in a hovel. The smells described by Black Death chroniclers—or at least some of them—seemed to emanate from inside the victim, as if his insides were gangrenous. Dr. Gage, who has fought plague in Asia and North and South America, cannot recall ever encountering a case of central nervous system involvement in a plague victim.

  Bubonic plague is the most
survivable of the three forms of the disease. Untreated, it has a mortality rate of about 60 percent.

  Pneumonic is the second type of plague, and—uniquely—it can spread directly from person to person. However, like other forms of the infection, it is borne in the rodent/insect connection. In some cases of bubonic plague, bacilli escape the lymph system and infect the lungs, causing secondary pneumonic plague. As the victim begins to cough and spit up blood—the principal symptoms of the “coughing” plague—the disease breaks free of the flea connection and spreads into the population like a cold or flu—through the air. Though summer outbreaks occur, pneumonic plague is more frequent in winter, when the colder temperatures favor the transmission of pulverized and frozen sputum and cough droplets.

  As with bubonic plague, there are also some notable differences between the modern variant of the “coughing plague” and its Black Death counterpart. One is incidence. Relatively uncommon today, during the first year of the Black Death pneumonic plague seemed to be everywhere in Italy and southern France. The other notable difference involves contagiousness. Modern pneumonic plague is not a particularly “catchy” disease, nor should it be. Plague bacteria are larger than viruses and thus harder to transmit directly from person to person—the bigger bacilli require bigger air droplets, and if they do reach another person, tend to get “stuck” in the upper respiratory system before they can reach the lungs.

  Even making allowance for the medieval propensity to exaggerate, one gets the impression that the pneumonic plague of the Black Death was not merely highly contagious but explosive in the manner of a nuclear chain reaction. “Breath,” wrote one horrified Sicilian chronicler, “spread the infection among those speaking together . . . and it seemed as if the victim[s] were struck all at once by the affliction and [were] shattered by it. . . . Victims violently coughed up blood, and after three days of incessant vomiting for which there was no remedy, they died, and with them died not only everyone who talked with them but also anyone who had acquired or touched or laid hands on their belongings.”

  The “coughing plague” is extremely lethal. If it goes untreated, the mortality rate in its victims is between 95 and 100 percent.

  No one survives untreated

  septicemic plague, the third form of the disease. The shocklike movement of massive amounts of plague bacilli directly into the blood system creates such enormous toxicity that even insects normally incapable of transmitting

  Y. pestis, such as body lice, can become disease vectors. During one outbreak of septicemic plague in the early twentieth century, the average survival time from onset of symptoms to death was 14.5 hours.

  There have been suggestions that the horrible disfigurement caused by septicemic plague—the extremities become as black and hard as coal—inspired the term Black Death, but septicemic disease is uncommon, and, in any event, the application of the terms “Black Death” to the medieval plague grew out of an old historical error. In 1631, a historian named Johannes Isaacus Pontanus, perhaps thinking of Seneca’s use of the Latin term for Black Death—

  Arta mors—to describe an outbreak of epidemic disease in Rome, claimed that the phrase had been current during the fourteenth-century mortality. The Swedes, who began using the expression around 1555 (

  swarta döden), the Danes, who adopted it fifty years later (

  den sorte Død), and the rest of Europe, which began using the expression “Black Death” in the eighteenth century, may have been laboring under the same misapprehension. The generation who lived through the medieval pestilence called it

  la moria grandissima, la mortalega grande, très grande mortalité, grosze Pestilentz, peligro grande, and

  huge mortalyte: names that translate roughly as the “Great Mortality,” or, more colloquially, the “Big Death.”

  One of the great mysteries of the medieval plague is how the fleeing Genoese survived the sixteen-hundred-mile sea journey from Caffa to Sicily, where the disease enters European history. Even if the escaping galleys stopped first in Constantinople and other ports en route to Italy as seems likely, getting caught on an open sea with

  Y. pestis would have been akin to getting caught in a revolving door with a rattlesnake. The only current explanation for the riddle is lucky genes. Recent research suggests that an allele,* CCR5-∆32, may confer protection against plague. Possibly some of the crew members had the requisite lucky allele.

  Clearer is what happened once Caffa slipped below the horizon. On the second or third day at sea a mariner awakes feeling feverish; after he falls asleep again, a shipmate steals his flea-infested jacket; a few days later, the thief is ill. As word of the men’s illness spreads through the ship, panicky crew members gather in the horse stalls on the lower deck to share rumors and conspire. That night there is a splash off the aft side of the ship, then a second; no one raises an alarm as the bodies sink below the surface in a cone of rippling moonlight.

  As the days lengthen and the disease takes hold, men begin to turn on one another, as they will later in Europe, when the plague arrives. There are beatings, murders, summary executions, mutinies; only the progress of the pestilence prevents complete anarchy. Men become too ill to kill, then too ill to work. A helmsman with a neck bubo is strapped to the helm; a ship’s carpenter with a bloody cough, to his bench. A rigger shaking with fever is lashed to the mast.

  Gradually each escaping vessel becomes a menagerie of grotesques. Everywhere there are delirious men who talk to the wind and stain their pants with bloody anal leakages; and weeping men who cry out for absent mothers and wives and children; and cursing men who blaspheme God, wave their fists at an indifferent sky, and burble blood when they cough. There are men who ooze pus from facial and body sores and stink to high heaven; lethargic men who stare listlessly into the cruel, gray sea; mad men who laugh hysterically and dig filthy fingernails into purple, mottled flesh; and dead men, whose bloated bodies roll back and forth across pitching decks until they hit a rail or mast and burst open like piñatas.

  In the thousand days between the autumn of 1347—when the Genoese arrived in Sicily, so diseased “that if anyone so much as spoke with one of them, he was infected”—and the winter of 1351–52, when the plague crossed the icy Baltic back into Russia,

  Y. pestis drew a hangman’s noose around Europe.

  From Sicily, where it raged unceasingly for a dozen months, one strain of the pestilence swept westward along the Mediterranean coast to Marseille, where half the city may have perished in the bitter winter of 1347–48. Sweeping up the Rhône to Avignon, in April 1348 the plague ended one of the mythic love stories in Western literature, exposed the moral weakness of a pope, and inspired nightly marches to the local cemeteries by Avignon’s hungry pigs. Farther to the east, in the Adriatic port city of Ragusa, authorities celebrated spring’s arrival by ordering all citizens to make out a will. In June the plague visited Paris, where the municipal cemetery ran out of burial space and the renowned Paris medical faculty pronounced the cause of the disease to be “an unusual conjunction of Saturn, Mars, and Jupiter at one on the afternoon on March 20th, 1345.” Later that bleak summer the plague forked like a serpent’s tongue. One strain swept northward toward Tournai on the Flemish border, where church bells rang unceasingly for two days to announce its arrival; while a second strain, enticed by the scent of war and death around recently besieged Calais, rolled up the coast and peered westward across the channel toward England. On the other side, from Dover to Land’s End, anxious Englishmen scanned the summer seas as they would not scan them again until the Battle of Britain in the summer of 1940.

  In July

  Y. pestis slipped through the cordon of watchers and entered the little port of Melcombe; a month later the town was still, except for the pounding of rain on village rooftops and the crash of surf against the chalky Dorset cliffs to the south. In the terrible month of September, the pestilence pivoted and wheeled eastward through an incessant late summer downpour toward London, where a griev
ing king mourned a beloved child. “No fellow human being could be surprised if we were inwardly desolated by the sting of this bitter grief, for we are human, too,” wrote Edward III of his plague-dead daughter, fifteen-year-old Princess Joan. In the spring of 1349, as the green hills of Wales echoed with birdsong, a local poet wrote, “Death comes into our midst like black smoke.” In the merry month of May

  Y. pestis arrived in Derbyshire, where in three short months it killed peasant William de Wakebridge’s wife, father, sister, a sister-in-law, and an aunt. Across the Irish sea, in Dublin, where the living had surrendered the streets to the dead, Franciscan John Glynn wrote, “I . . . am waiting among the dead for death to come.”

  Another strain of the plague entered Europe through Genoa, where several galleys laid anchor on the last day of 1347. As a raw winter wind whipped through the city’s nighttime streets, a candle glowed in the window of local notary Antonio de Benitio, who remained in the infected city to make out wills for clients unable to flee. Swinging inland across the narrow plains of central Italy, the plague swept into Florence on a cold March day and killed so many of its citizens, church bells were stilled to preserve public morale; “the sick hated to hear [them] and it discourages the heathy as well,” wrote a survivor. In June, when the plague arrived in Siena, a tax collector and former shoemaker named Agnolo di Tura declared, “This is the end of the world.” Nearby Pistoia greeted the pestilence more pragmatically. “Henceforth . . . ,” declared the town fathers, “each grave shall be dug two and a half arms’ lengths deep.” In August the pestilence reached Perugia, where Gentile da Foligno, one of Italy’s most celebrated physicians, cast his lot with the poor. As the wealthy and well-born of Perugia fled, wealthy, well-born da Foligno remained at his post, visiting the stinking hovels of the needy until, at last, the plague claimed him.