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The Black Death

Stained glass image of Death and his horse

In the mid-summer of 1348, the Black Death first arrived in England.  Within two years over one third of the population of the British Isles would be dead.

“I looked, and behold a pale horse: and his name that sat on him was Death, and Hell followed with him”

[Revelation 6:8]

A day like any other

It was shortly before 24th June 1348 in the port called Melcombe (now more commonly known as Weymouth). It was a day like any other and the port was as busy as ever, with ships carrying rich cargos coming and going.  Some of the arrivals that day had come from other English ports and some from the continent. 

Weymouth may seem like a minor port these days but back in the Middle Ages it was a big deal.  In fact, it was one of the largest ports in England, a major hub for the export of wool and the import of wines.  It provided easy and convenient access to France and trade with the English held territories there (especially Gascony in the southwest) was brisk.

A ship arrived that day from Gascony, an entirely unremarkable event in the daily life of Melcombe.

But it would prove very far from unremarkable.

One of the sailors on board this ship had taken sick.  He was probably brought ashore so that he could convalesce in a proper bed.  But it proved to be no ordinary sickness for, in the words of one Chronicler, this fellow…

“…had brought with him from Gascony the seeds of the terrible pestilence and through him the men of that town of Melcombe were the first in England to be infected”

[Grey Friars Chronicle]

The ‘terrible pestilence’ to which he was referring was the Black Death.

We see death coming into our midst

Over the next few weeks, the plague spread out rapidly, devastating the port of Melcombe and quickly infecting nearby villages and towns.  The fatality rate was colossal; England was facing by far and away the most lethal pandemic in her history.

The plague was spreading not just across England but across the whole of Europe.  Within just five years of its initial arrival in the Sicilian port of Messina in October 1347, it had reached every corner of the continent.  England escaped unscathed until the middle of 1348, but people had no doubt heard terrible rumours of its progress.  Now it was here, and, during the second half of 1348, it spread across England like wildfire.

Map showing the spread of the bubonic plague 1347 - 1351

The chronicler, Geoffrey the Baker, described its devastating progress in the Chronicon Angliae:

“…in Dorsetshire, where, as in other counties, it made the country quite void of inhabitants so that there were almost none left alive. From there it passed into Devonshire and Somersetshire, even unto Bristol, and raged in such sort that the Gloucestershire men would not suffer the Bristol men to have access to them by any means. But at length it came to Gloucester, yea even to Oxford and to London, and finally it spread over all England and so wasted the people that scarce the tenth person of any sort was left alive.”

[Geoffrey the Baker, Chronicon Angliae]

The plague ravaged local communities at a frightening rate.  In most parts of the country, once the plague had arrived, it would devastate the local population in a matter of a few short weeks. 

To many people in the Middle Ages the Black Death must have seemed like an apocalyptic event.  To witness such a large proportion of the population dying so quickly, all around you, is hard to even image.  The Welsh poet, Jeuan Gethin wrote in 1349:

“We see death coming into our midst like black smoke, a plague which cuts off the young, a rootless phantom which has no mercy or fair countenance.” 

[Jeuan Gethin, 1349]

Jeuan himself died of the pestilence shortly after writing this, at some time in the spring of 1349.

The end of days

To people in the Middle Ages, with no knowledge of modern medicine, the only thing they could turn to was prayer.  Pilgrimage to holy sites was a major feature of medieval life, especially at times of crisis.  As the Black Death spread, it must have seemed like only divine aid could save you.  People flocked to the shrines and holy places to entreat the saints to intercede on their behalf. 

Of course, as people gathered at these sites in significant numbers, it provided the ideal conditions to spread the infection.

Some people even wondered if it might be the end of days.  With so many dying all around you, it is only natural to wonder – will anyone survive?  In Ireland, Brother John Clyn of Friars Manor in Kilkenny pondered this very thought.  His account of the plague is recorded in his chronicle and ends as follows:

“I leave parchment for continuing the work, in case anyone should still be alive in the future and any son of Adam can escape this pestilence and continue the work thus begun.”

[Brother John Clyn, Friars Manor chronicle]

Underneath this, is one final entry, written in a different hand:

“Here, it seems, the author died.”

[Anon. Friars Manor chronicle]

The city was teeming with corpses

The death toll was horrendous.  All across Europe people were dying in their millions.  Writing in Florence, the chronicler, Marchionne di Coppo Stefani, summed up the unimaginable scale of the catastrophe:

“All the citizens did little else except to carry the dead bodies to be buried… . . . At every church they dug deep pits down to the water level; and thus those who were poor who died during the night were bundled up quickly and thrown into the pit. In the morning when a large number of bodies were found in the pit, they took some earth and shovelled it down on top of them; and later others were placed on top of them and then another layer of earth, just as one makes lasagne with layers of pasta and cheese”

[Marchionne di Coppo Stefani]

In some places so many died that there weren’t enough people left alive to bury the dead fast enough:

“A great many breathed their last in the public streets, day and night; a large number perished in their homes, and it was only by the stench of their decaying bodies that they proclaimed their death to their neighbours. Everywhere the city was teeming with corpses.”

[Boccaccio, Decameron, (trans. Winwar, p. xxviii)] 
Medieval picture of dead being buried

But then, just as quickly as it had struck, the Black Death passed. 

The final death toll

By the start of 1350, just 18 months after it had first arrived, the plague had swept through England and largely burnt itself out.  Scotland and Ireland would continue to suffer for a while yet but by the end of the year, it would mostly be over.

There would be further outbreaks in the future.  The plague would continue to bring death to the British Isles until the eighteenth century.  Subsequent outbreaks, however, would never be as devastating as the first wave of 1348-1351.

There have been several different estimates of the final death toll.  Some put it as low as 30%, others as high as 60%.  However, all agree that the death toll was staggeringly high – higher than any other global pandemic before or since.

Professor Ole J. Benedictow of the University of Oslo believes that:

The data is sufficiently widespread and numerous to make it likely that the Black Death swept away around 60 per cent of Europe’s population.”

[Professor Ole J Benedictow, The Black Death: The Greatest Catastrophe Ever]

As Europe’s population in the mid-C14th was in the order of 80 million, a 60% death rate meant that around 50 million people died.  That is more than the total number of people murdered by Hitler and Stalin combined.

At the time no one had any idea what caused the plague.  A punishment from God?  Or perhaps even one of the four horsemen of the apocalypse heralding the end of days?

A doctor in Hong Kong

It was not until 1894 that a student of Louis Pasteur by the name of Alexandre Yersin came up with a more scientific answer.  He studied an outbreak of plague in Hong Kong in 1894, looking for clues as to the possible cause.  He found that a bacterium (Yersinia Pestis) was present in the plague victims and that the same bacterium was also present in rats.  The theory soon developed that this bacterium caused bubonic plague and that it was being transmitted from rats to humans via infected fleas.  

For a long time, this theory was widely accepted.  However, in more recent times it has been called into question. 

A frightening question

In a 2001 article in the New Scientist a pair of Liverpool University epidemiologists challenged Yersin’s conclusions.  They argued that, given the rapidity at which the plague spread, and what we know of rat populations in Europe, the idea that the Black Death was bubonic plague just didn’t stack up. 

They identified several problems with the bubonic plague theory.  How could the plague have spread across the Alps so fast in temperatures at which rat flea eggs just would not hatch? Why was the rate of spread over long distances significantly faster than anything you’d expect from a rat born infection?  In India, in 1907, an outbreak of rat born bubonic plague took six months to move just 300 feet!  And why was it that the Black Death killed 30%-50% of the population but in the 1907 Indian outbreak the death rate from bubonic plague was just 2%?

One of the researchers involved, Sue Scott, commented at the time:

“If you look at how the Black Death spread, one of the least likely diseases to have caused it is bubonic plague.”

[Sue Scott, quoted in the New Scientist; Did bubonic plague really cause the Black Death? 2001]

So, was the Black Death a different disease?  Something other than bubonic plague? 

This raises the frightening prospect that the Black Death is a completely unknown disease.  Something that swept virulently across Europe in our distant past but is now long gone.  Something which, perhaps, is just lying dormant, ready for the conditions to be right for it to strike again.  

Might it, whatever it was, one day return?

A frightening prospect.

The search for the Black Death

One way to find out what caused the Black Death is to examine the remains of its victims.  Plague pits exist across Europe, containing the remains of thousands of people who died from the pestilence.  In some cases, these are well enough preserved to allow scientists to take viable organic samples.  If enough material can be recovered, it is possible to detect traces of bacteria, such as the Y. pestis bacterium that causes bubonic plague.

In 2010, a paper was published based on a laboratory analysis of 76 different skeletal remains of plague victims from England, France, Germany and Italy.  Not all yielded viable samples for analysis but those that did revealed a common pattern.  The researchers concluded…

“… humans buried in mass graves that were historically and contextually associated with the Black Death and its resurgences, were consistently infected by Y. pestis in southern, central and northern Europe.”

[Distinct clones of Yersinia pestis caused the Black Death, 2010]

So, if the Black Death was definitely Y.Pestis, how did it spread so fast?  To spread that quickly it must have been transmitting from human-to-human as well as from rat to human.  But how? 

Pneumonic plague

One possible answer is pneumonic plague.  In some forms of the Y.pestis infection, the disease can reach the lungs.  This form of the disease is pneumonic plague.  Now, unlike bubonic plague, pneumonic plague can be transmitted from person to person.  This is because when pneumonic plague victims cough, they release a spray of pathogen bearing droplets into the air.  Anyone unlucky enough to inhale any of these droplets risks becoming infected. 

So, could the pneumonic form of the disease explain the rapid spread of the Black Death?

The only problem with this explanation is that pneumonic plague outbreaks are usually small and localised.  This is because the rate of infection is so rapid that the infected local population dies off before they can spread the disease over a wider area.   In an urban environment it is easy to see how a pneumonic plague outbreak could be devasting.  However, this form of the disease would struggle to spread over long distances in rural areas.  But the Black Death did just that.  Its ability to spread rapidly over long distances in rural locations is attested on several occasions.

The pneumonic plague theory can account for some transmission, but it isn’t a fully adequate explanation.

A new theory

We had to wait until 2018 before further scientific research identified another way by which Bubonic Plague could spread so quickly.  This new theory made a lot more sense in the context of medieval Europe.  It also explained why we rarely see any outbreaks of Black Death in the world today.  And this is despite the fact that neither humans, nor rats, nor rat fleas, nor the disease itself, are that much different today than in 1347 when the plague first arrived in Sicily. 

But, as it turns out, something is very different today.  Something else.

With the benefit of hindsight, the clues were there all along.  At time of the Black Death the chronicler John Fordun (d.1384) wrote in the Scotichronicon:

“…This sickness befell people everywhere, but especially the middling and lower classes, rarely the great.”

John Fordun, Scotichronicon]

What was it that was so special about the ‘great’ that made them so resilient to the Black Death?  Surely, it could not be their blue blood that was somehow protecting them! 

As it turns out, the reason Black Death spread so fast back then but is unable to do so today simply comes down to this:  human ectoparasites.  More specifically that means human fleas and lice. 

Why no Black Death today?

Nowadays, human fleas and lice are rare.  People who suffer from infestations of such pests quickly take steps to get rid of them.  Back in 1347 this was not the case.  A large proportion of the Medieval population, especially the poor and the middling, were infested with fleas and lice.  The only section of the population who were relatively free of these pests were, you guessed it, ‘the great’.

Simply brushing up against someone in the street or sitting next to them in a tavern provided ample opportunity for an infected flea to hop onto you.  And one was all it took!  In Europe in the late 1340s the conditions were ideal for the plague to literally hop from one person to another, anywhere and everywhere people travelled.  It was in this way that the Plague spread with such devastating speed across all of England from a single infected Gascon sailor in Weymouth.

Work done on modelling possible methods of transmission for the Black Death in 2018, concluded:

“…in seven out of nine localities, the human ectoparasite model was the preferred model to explain the pattern of plague mortality during an outbreak, rather than models of pneumonic and rat–flea plague transmission.”

[Human ectoparasites and the spread of plague in Europe during the Second Pandemic, 2018]

So, when that Gascon sailor stepped ashore in Weymouth in June 1348 it was probably the human fleas that hopped ashore with him that brought the Black Death to England.

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References & further reading

Black Death.  10 November 2011. Dr Mike Ibeji.  BBC History.

Black Death Wikipedia

Did bubonic plague really cause the Black Death? 24 November 2001, Debora Mackenzie, New Scientist

Distinct Clones of Yersinia pestis Caused the Black Death.  7 October 2010. Haensch,Bianucci, Signoli,Rajerison,Schultz,Kacki, Vermunt,Weston, Hurst, Achtman,Carniel,Bramanti. US National Library of Medicine

Facts about Pneumonic Plague, CDC

Human ectoparasites and the spread of plague in Europe during the Second Pandemic, 6 February 2018, Dean, Krauer, Walløe, Lingjærde, Bramanti, Stenseth, Schmid.  PNAS

La peste bubonique a Hong-Kong. 1894. Yersin Alexandre. Annales de l’Institut Pasteur: Journal de microbiologie.

The Black Death: The Greatest Catastrophe Ever, History Today

The Scourging Angel: The Black Death in the British Isles. 2010. Benedict Gummer.  Vintage. 

University of Rochester – Death, Dying, and the Culture of the Macabre in the Late Middle Ages


Stained glass window of the Horseman of the Apocalypse – Peter Haas, wiki commons 

Burial of Plague victims – Miniature by Pierart dou Tielt. circa 1353.  Gilles li Muisis.

Map of the spread of bubonic plague in Europe – Roger Zenner

Photograph of Alexandre Yersin – Unknown photographer, 1893.

1 thought on “The Black Death”

  1. Ben Bergonzi

    What an excellent and well-researched article! Rather scary in the middle but reassuring by the end. I am very impressed, Paul, and will now read some more of your articles.

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