When the plague arrived at Catalonia’s doorstep in April 1348, the learned physician Jacme d’Agramont wrote to address the “doubts and fears” rising around him. He laid out, in a treatise written in Catalan to the civil authorities in his hometown of Lleida, a set of reasonable preventative measures that anyone could take. The air was likely putrefied because of sin, so confession should be the first priority. The windows should be sealed shut, the fire stoked with juniper, and the floor sprinkled with vinegar. One should eat and drink very little, and it should all be as sour as possible. “Slimy fishes” like eel and “rapacious fishes” like dolphin should absolutely not be eaten, nor ducks, nor suckling pigs. A little bloodletting could help. Sex and baths must be avoided, because they open one’s pores and allow noxious airs to enter. A fearful imagination would only make matters worse.

D’Agramont’s 1348 letter was the first plague tract. Others soon followed, and reading these tracts today is instructive. The plague’s progress out of Central Asia and into Europe and the Middle East was heralded by rumors of its advance. Rulers and ordinary people alike knew it was coming; they wanted to know how to prepare and how to endure what they knew would be a profound disruption to everyday life. “Experience shows us,” D’Agramont wrote, “that when a dwelling catches on fire all the neighbors become afraid.” Tracts like his aimed to calm the neighbors—the literate ones, at least, who could share the advice with the illiterate—by giving them a sense of control over a collective predicament that was, in fact, in nobody’s hands.

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D’Agramont’s advice was written without the benefit of direct observation. He drew on what he modestly calls the “little science” he’d gleaned from studying pestilences recorded in the Bible and Hippocrates. The plague tracts written subsequently, in the midst of the epidemic, struggled to describe a disease that physicians swiftly realized was not like the ones they had read about. Modern scholars debate the 1348 plague’s mortality rate (anywhere between 30 and 60 percent of the population) and the pathogen responsible (most historians agree that the bacterium yersinia pestis is to blame, but candidates from anthrax to hemorrhagic fever have been proposed). As the historian Monica Green has pointed out, “even its full geographic extent is still unknown.”

But all agree that it was unlike any earlier epidemic, killing tens of millions of people over the course of a few years. Medieval writers recognized this unprecedented quality: Guy de Chauliac, physician to the court of Pope Clement VI in Avignon, called it inaudita, unheard-of. While historians had long recorded pestilences, Guy wrote, “none of them occupied more than a single region, this one the whole world; they were curable in some way, this one not at all.” Others simply called it the “great mortality” or the “universal pestilence.” (Like the word “medieval,” “the Black Death” was a later invention, the coinage of a confused seventeenth-century historian.)

In May 1348, a week after d’Agramont sent his letter to the rulers of Lleida, the governing council or comune of the Tuscan town of Pistoia issued a set of ordinances intended to slow the spread of the disease. Travel bans were put in place and the transport of goods restricted. Polluting industries such as butcheries and tanneries were closed or strictly limited. Social gatherings like funerals and commemorative masses were banned, with some exceptions for people of rank: knights, lawyers, judges, and physicians could “be honored by their heirs at their burial in any way they please.”

Pistoia is now one of the centers of the coronavirus epidemic in Tuscany. Like the rest of Italy, it is under lockdown. Funerals and religious services are once again forbidden. The Florentine newspaper La Nazione reports that mass will be celebrated over Facebook and YouTube, while quarantined residents meet for an aperitivo over Zoom. Lacking such technological ingenuity, fourteenth-century “social distancing”—spurred by personal fear and collective regulation—severed the usual bonds of a close-knit society. In Avignon, France, Guy de Chauliac lamented that family ties had frayed in the face of the plague: “Fathers did not visit their sons, nor sons their fathers. Charity was dead, hope prostrate.”

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Medieval scholars thought the plague arose from causes both universal (unfortunate astrological conjunctions) and particular (corrupted airs and humoral imbalances). One can’t control the stars, but one can control what Greek medicine called the six non-naturals, the mutable things like exercise and emotion that were thought to affect health. Across both the Islamic and Christian medical worlds, writers warned against sex and baths and commended sour food and strong smells. In a 1348 report, the Paris Medical Faculty warned that certain populations were more susceptible to the disease: those “bunged up with evil hu­mors”; “those following a bad life style, with too much exercise, sex and bathing”; “persistent worriers”; “corpulent people with a ruddy complexion.” Lifestyle changes might therefore improve one’s chances. Others tried to offer suggestions for the care of the sick. De Chauliac prescribed an ointment of figs, onions, butter, and fermented dough for the buboes; the polymath Ibn al-Wardi recorded the doctors of Aleppo anointing his compatriots with Armenian clay.

Much of this advice was meant for home use. Many early plague treatises were written in local vernaculars rather than Latin, as d’Agramont put it, “for the benefit of the people and not for the instruction of the physician.” After the plague returned, in 1360–1361, the audience for plague advice grew even larger. John of Burgundy’s De epidemia, a post-1361 bestseller in multiple languages, instructed readers to take dietary supplements—“a dose of good theriac the size of a bean”—and to sniff aromatics in cold weather, with shopping suggestions broken out by budget level: “ambergris, musk, rosemary and similar things if you are rich; zedoary, cloves, nutmeg, mace and similar things if you are poor.” Sometimes the plague sufferer was allowed a cheat day: in lieu of wine, a patient should drink vinegar in water, but “occasionally, however, he can be given, to cheer him up, white wine diluted with plenty of water.” By the fifteenth century, the English poet John Lydgate could sum up such advice with a cheerful jingle: “Drynk good wyn, & holsom meetis take, / smelle swote thynges,” he wrote, “walke in cleene heir, eschewe mystis blake.”

Such instructions provided a way to wrest agency back from a traumatic experience of collective vulnerability. The past few weeks have seen similar efforts on social media, which has begun to feel like a live-updating plague tract. Reminders to stay in, to wash our hands, to “#flattenthecurve” mark earnest attempts to conform individual behavior to the needs of collective well-being. But they do little to remedy our sense of powerlessness. They certainly don’t allay the chief concern of the young and asymptomatic, which is the risk of infecting the vulnerable people around them. Harvard, where I teach, shut down classes and evicted undergraduates from the dorms. (When plague hit medieval Oxford, the scholars scattered into the countryside, too.) During our last meeting in person, my students worried that they might unknowingly carry Covid-19 home to their parents and grandparents. I could think of no real reassurance to offer them.

So we search for everyday commodities to assuage our anxiety: rice, cleaning supplies, toilet paper. As I’ve been writing this piece, I’ve found myself besieged by scammy Internet ads for masks, which our government begs us not to buy. Before the pandemic was widespread in the United States, an email purportedly written by a distinguished scholar of coronaviruses was widely shared on Facebook. It said the usual things—wash your hands and sneeze into a tissue, etc.—but also suggested that zinc might impede the infection. Zinc lozenges suddenly became the theriac to cure all ills; masks and hand-sanitizer, the ambergris and zedoary to ward off infection.

Of course, putting faith in the efficacy of our actions is also meant to stave off despair. Even as Covid-19 took hold, doctors, nurses, and quarantined patients recorded music videos and dance-offs to raise people’s spirits. As the pandemic has spread, people under lockdown in Italy have taken to their balconies to sing. As d’Agramont put it, “in such times, joyfulness and gaiety are most profitable.”

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Not long after finishing his letter, d’Agramont himself contracted the plague and died. Ibn al-Wardi succumbed in Aleppo in 1349. Guy de Chauliac caught it in Avignon in 1348; for six weeks, he languished with a fever as a bubo swelled in his groin. He recovered and slipped a memoir of his experience into a chapter on ulcers of the breast in his Chirurgia magna, a compendium of knowledge—written because “not everyone can have every book, and even if they could, it would be tedious to read them and godly to retain it all in mind”—that was copied, translated, and used as an authoritative reference for centuries to come.

This book’s fifteenth-century English translation includes one of the language’s earliest examples of the word “crisis.” In Middle English, the term referred to the determinative phase of an illness, the point from which one either recovers to health or declines to death. Its etymological origins can be traced back to Greek κρῐ́σῐς (krisis)—also related to modern English “critic” and “critique”—a word that denotes separation, dispute, decision, and judgment. De Chauliac’s English translator explained the term with a Middle English gloss: “determynacioun.” The crisis is the moment of decision, the place where individual and collective suffering meet.

Plague and crisis thus entered Anglophone consciousness hand in hand. Histories medieval and modern still reflect that association. Monastic chroniclers recorded the pestilence as just one aspect of a general calamity in the 1340s, heralded by earthquakes and an unusually warm winter, accompanied by war and famine. A longstanding grand narrative holds that the Black Death was the hinge of a larger “crisis of the fourteenth century”: the pandemic sent the European feudal order into disarray, and eventually modernity emerged from the pesthouse.

The coronavirus may be remembered likewise—as an indelible historical dividing line, but also as a symptom of a broader crisis. In their 1348 bulletin, the Paris Medical Faculty observed that the “winter was not as cold as it should have been.” The faculty attributed the problem to Mars, which was “looking upon Jupiter with a hostile aspect.” We know that our warm winters are not the product of astrological misfortune but of two centuries of fossil-fuel extraction and consumption. The effects of climate change will likely spur more pandemics. As this one continues to spread, pulling down the world economy with it, more people will suffer and die. The poor and vulnerable will suffer more, as they already do, in disasters that unfold routinely beyond public attention.

There is no reason to think that our governments are equipped to address the social ramifications of these disasters. In fact, we risk repeating the worst mistakes of the past. As the historian of science Hannah Marcus recently pointed out in The New York Times, “foreigners, prostitutes, Jews and the poor were blamed for outbreaks of plague.” Some medieval physicians, clerics, and rulers rejected such hate and superstition, but others encouraged it: d’Agramont warned that someone was poisoning wells; the French poet and composer Guillaume de Machaut attacked “shameful Judea” and celebrated the anti-Semitic pogroms that took place across Europe. Such retributive violence followed the cues of what the historian R.I. Moore labeled the medieval European “persecuting society.” There is no evidence of similar treatment’s being meted out to religious minorities in the equally plague-stricken Islamic world. America has met the coronavirus with racist scapegoating and politically opportunistic Sinophobia. As most nations retreat behind their borders, our shared descent into authoritarianism, nationalism, and xenophobic violence may well accelerate.

Against division, medieval plague tracts aimed to serve what d’Agramont called “the common and public good.” But the advice they offered emphasized a personal regimen that could scarcely slow the spread of the plague or diminish its effects. Their prescriptions reveal the limits of individual action in combating such a shared predicament as a pandemic. As we wait in quarantine and under lockdown, we should join together in whatever forums are available to us to ask ourselves what kind of future we can make together when we emerge.