The Black Death

The word quarantine comes from quaranta, Italian for forty, the number of days some ports made travellers wait after the Black Death.

A disease from central Asia

The Black Death was an epidemic of plague, caused by the bacterium Yersinia pestis, that swept across western Asia, North Africa and Europe from 1346 to 1353. Plague lives in wild rodents such as marmots and is passed on by the bite of their fleas. It can spread through rats that live close to people, and in its pneumonic form, when it infects the lungs, it passes from person to person in coughed droplets. For a long time the starting point was argued over. In 2022 a team publishing in Nature recovered plague DNA from people buried in two cemeteries, Kara-Djigach and Burana, near Lake Issyk-Kul in modern Kyrgyzstan, where gravestones dated 1338 and 1339 give pestilence as the cause of death. The ancient genomes sit right at the point where the plague strains linked to the Black Death branch out, which supports a start in that part of central Eurasia about eight years before plague reached the Black Sea.

From Caffa to Messina

By 1346 plague had reached the Golden Horde on the lower Volga and the shores of the Black Sea. That year the khan Janibeg was besieging Caffa, a Genoese trading port in Crimea, today Feodosia. A notary from Piacenza, Gabriele de’ Mussi, later wrote that the besiegers, dying of plague, threw corpses over the walls with catapults. He was probably not there, and historians doubt this was how the disease got in, since rats and fleas cross walls easily. Whatever the route, ships carried plague west. It reached Constantinople in 1347, and by October 1347 it was in Messina in Sicily; a Franciscan friar, Michele da Piazza, wrote about ten years later that it arrived on twelve Genoese galleys. From the ports it moved inland along roads and rivers. Marseille, Florence and Paris were struck in 1348. Britannica says it reached southern England in 1348 and northern Britain and Scandinavia by 1350.

How many died

No one counted the dead reliably at the time, so historians work from tax lists, church records and the rolls of manor courts (unit 4). Britannica estimates that about 25 million people died in Europe between 1347 and 1351, a figure often summed up as a third of the population; some modern estimates go higher, to half or more, and the toll varied greatly from place to place. In crowded towns it was not unusual for half the people to die. Giovanni Boccaccio described Florence in 1348 at the start of the Decameron: neighbours stopped visiting the sick, some parents abandoned their children, and when the churchyards were full the dead were laid in great trenches, layer upon layer, like cargo in a ship. Plague came back every decade or two for centuries, and Europe’s population took more than a century to recover.

What people did, and what changed

Physicians of the time blamed bad air, miasma, or the stars; in 1348 the medical faculty of Paris pointed to a conjunction of Saturn, Jupiter and Mars in 1345. Some people joined processions of flagellants who whipped themselves in public penance. In many towns of the Rhineland and beyond, Jews were falsely accused of poisoning wells and murdered, even though Pope Clement VI issued bulls in 1348 rejecting the accusation. Towns also tried practical measures. On 27 July 1377 the Great Council of Ragusa (Dubrovnik) ordered that newcomers from plague areas spend 30 days in isolation before entering the city; in the following decades the period was stretched to 40 days, the quarantine. In the longer run, with far fewer workers, surviving peasants could demand higher wages and better terms. In England the Ordinance of Labourers (1349) and the Statute of Labourers (1351) tried to hold wages at the old level, and the resentment fed into the Peasants’ Revolt of 1381.