Explaining a disaster
No one in the fourteenth century knew that plague was caused by a bacterium carried by fleas. Germ theory lay centuries in the future. Explanations instead drew on the religion, astronomy and medicine of the day, and they often overlapped. Understanding what people thought is the key to understanding what they tried.
Three broad explanations were common. The first was divine punishment: God was angry with a sinful world. The second was a corruption of the air, called miasma, caused by poisonous vapors from the earth, from rotting matter, or from the heavens. The third was the influence of the stars. Many writers combined them, so that planets could be said to corrupt the air as an instrument of divine will.
The Paris report and the planets
A frequently cited example is a report written in 1348 by the medical masters of the University of Paris at the request of the French king. It is generally summarized as blaming a conjunction of planets in 1345, which was thought to have drawn up corrupt vapors from the earth and sea. This reasoning drew on medieval astrology, which was treated as a respectable branch of learning and often as part of medical practice. The report also offered practical advice, covering diet, sleeping habits and avoiding bad air.
What physicians recommended
Learned medicine rested on humoral theory, the idea that health depended on the balance of four bodily fluids. Under that system, a physician might try to restore balance, and plague advice typically included:
- avoiding foul smells and marshy or crowded places, and sometimes burning aromatic woods or herbs to cleanse the air;
- moderate eating and drinking, avoiding foods thought to encourage corruption;
- bloodletting, sometimes in a spot chosen to match the location of the swelling;
- lancing or poulticing the buboes;
- carrying scented items or sweet-smelling herbs.
Treatments of this kind could not cure a bacterial infection. Some of the practices, such as lancing a bubo with unclean tools or bleeding a weakened patient, may have done harm. Others, like leaving a crowded place, could occasionally help by chance, though they were not understood that way. Alongside the learned doctors, many people turned to local healers, apothecaries and traditional herbal remedies, and some of the more expensive medicines claimed to contain rare ingredients. Many of these preparations were commercial products of uncertain value.
Flight and isolation
Those with means often fled to the countryside, and contemporaries noted this. The idea behind it, avoid the corrupt air of the city, was not wrong in effect, since leaving an infected area can reduce exposure, but travelers sometimes carried infection with them.
Some authorities went further. Italian city governments, in particular, began to experiment with measures such as closing the gates to travelers from affected areas, restricting the movement of goods, appointing health officials, and isolating the sick. Milan is traditionally credited with severe isolation measures in the early outbreak. In 1377 the port of Ragusa, now Dubrovnik, required arriving ships and travelers to wait for a set period, thirty days, before entering. Venice and other ports later used a longer waiting period, and the Italian word quarantena is linked to the forty days that came to be used. These measures were not based on knowledge of germs, but they were built on the observation that the disease moved with people and goods, and they are often seen as early public health.
Prayer, processions and penance
Religious responses were at least as important as medical ones. Communities held processions carrying relics and images, orders of masses were said, and people sought the protection of saints. The belief in prayer and healing was widespread, and saints associated with plague became prominent in this period and afterward. Many people made donations or vows, hoping to win divine mercy.
At the extreme end were the flagellant processions, in which penitents whipped themselves to atone for the sins thought to have caused the disaster. The Church eventually condemned them. Elsewhere, hospitals and religious houses cared for the sick, though in many places the caregivers suffered high mortality themselves.
Blame and fear
Where explanations pointed to hidden poisoners or conspirators, fear could turn violent. In some regions rumors that Jews had poisoned wells led to massacres. These events are covered in a separate article on persecution, but they belong to the same story: explanation and remedy were tangled up with the search for someone to hold responsible.
Did anything work?
Individually, little did. A person who caught pneumonic plague in the fourteenth century had a very poor chance regardless of the treatment. At the community level, isolation and restricting movement probably helped in some places, even if the reasons were misunderstood. Over the following centuries, health boards, quarantine stations and record-keeping became standard features of European cities, and this institutional legacy may be the plague’s most lasting medical consequence.
A note on imagery: the beaked mask often associated with plague doctors comes from the seventeenth century, not the fourteenth. In the 1340s, physicians had no such costume.