The English Sweating Sickness: A Mysterious Plague

The English Sweating Sickness


Sweating sickness, colloquially referred to as “the sweats,” held various monikers such as English sweating sickness, English sweat, and sudor anglicus in Latin. This enigmatic and contagious ailment emerged in England and subsequently spread across continental Europe, initiating a series of epidemics that commenced in 1485. Strikingly, the disease abruptly appeared and disappeared in a puzzling manner, with the last recorded outbreak taking place in 1551. Its rapid onset of symptoms often led to swift fatalities, sometimes within mere hours.

Distinctive Characteristics of Sweating Sickness Epidemics

In contrast to prevalent disease outbreaks of its era, the sweating sickness epidemics stood out due to their unique attributes. Unlike the sustained and urban-focused nature of many epidemics, instances of sweating sickness exhibited rapid spikes and subsequent declines. Notably, the disease wielded a particularly heavy impact on rural populations.

Epidemic Patterns and Disappearances

Commencing its scourge in 1485, the sweating sickness inflicted repeated epidemics throughout the ensuing years. The swift and severe nature of its attacks left communities reeling. However, an intriguing aspect was the sudden vanishing of the disease after the 1551 outbreak. Following this occurrence, sweating sickness seemingly faded from existence, leaving behind an aura of mystery.

Unveiling the Enigma: The Unknown Cause

Despite extensive study and speculation, the root cause of sweating sickness has remained elusive. Hypotheses have abounded, yet no definitive conclusion has been reached. One notable theory proposes the involvement of an unidentified hantavirus species as the potential culprit. However, this remains speculative, leaving the question of the disease’s origin unanswered.

Sweating Sickness In a Nutshell by Claire Ridgway
Sweating Sickness In a Nutshell by Claire Ridgway

Clinical Presentation of Sweating Sickness

Historical Insight: John Caius’ Observations

In the year 1551, amidst an outbreak in Shrewsbury, physician John Caius meticulously documented the signs and symptoms of the disease. His work, titled “A Boke or Counseill Against the Disease Commonly Called the Sweate, or Sweatyng Sicknesse” (1552), remains a pivotal historical reference for understanding this affliction.

Onset and Early Symptoms

The disease manifested abruptly, commencing with a prevailing sense of apprehension. This initial feeling was followed by intense cold shivers, occasionally violent in nature, accompanied by sensations of dizziness, headaches, and excruciating pains in the neck, shoulders, and limbs. These distressing sensations were accompanied by profound exhaustion.

Stages of the Disease

The cold stage persisted, varying from half an hour to three hours. Subsequently, the transition to the hot and sweating stage occurred. Notably, the distinctive sweating would suddenly emerge without any apparent trigger. This stage was marked by a sensation of heat, severe headaches, delirium, rapid pulse, and an overwhelming thirst. Additionally, palpitations and cardiac pain were frequent occurrences. Notably, observers did not report any skin eruptions during these episodes.

Final Phases and Outcome

As the disease progressed, it culminated in either profound exhaustion and collapse or an intense urge to sleep, which John Caius believed to be fatal if succumbed to. It’s worth noting that experiencing one episode of the sickness did not confer immunity, and some individuals endured multiple bouts before succumbing to the disease. The typical course of the ailment spanned a full day before either recovery or demise ensued. Interestingly, the disease exhibited a seasonal pattern, predominantly affecting individuals during the summer and early autumn.

Thomas Forestier’s Account

In 1485, physician Thomas Forestier recounted his personal encounters with the sweating sickness during the initial outbreak. Notably, he highlighted the sudden onset of breathlessness commonly witnessed during the final hours of sufferers. Forestier’s observations extended further, suggesting the accumulation of “loathsome vapors” around the heart and lungs. These observations provided intriguing hints of a pulmonary dimension to the disease’s pathology.


The mode of transmission largely remains an enigma, supported by scanty fragments within historical writings. The ailment appeared to disproportionately affect young men while displaying a preference for the affluent or influential individuals. This led to the coining of monikers like “Stoop Gallant” or “Stoop Knave,” symbolizing the humbling of the proud to relinquish their elevated status. The emergence of terms like “Stoop Gallant” and “Stoop Knave” underscores the social dynamics at play, where societal hierarchies were disrupted by the disease’s impact on the wealthy and powerful. The substantial gathering of people in London to witness the coronation of Henry VII potentially facilitated the wider dissemination of the disease.

Mysterious Origins of the English Sweating Sickness

Historical Speculation and Outbreaks

The exact cause of the English Sweating Sickness remains a mystery. Over the years, commentators have pointed fingers at various factors such as sewage, poor sanitation, and contaminated water supplies. The earliest confirmed outbreak dates back to August 1485, following the Wars of the Roses. There’s speculation that this disease might have been introduced to England by French mercenaries from France, as suggested by the outbreak’s timing. Nevertheless, historical records raise the possibility of an earlier outbreak in June 1485 in York, preceding the arrival of Tudor’s army, although insufficient symptom descriptions make this uncertain. The Croyland Chronicle notes that Thomas Stanley, 1st Earl of Derby, cited the sweating sickness as a reason to abstain from joining Richard III’s army prior to the Battle of Bosworth.

Relapsing Fever Hypothesis

One proposed cause is relapsing fever, transmitted by ticks and lice. This disease typically emerges during the summer, akin to the original sweating sickness outbreak. However, relapsing fever is characterized by a distinctive black scab at the tick bite site and subsequent skin rash, setting it apart from the sweating sickness symptoms.

Ergot Poisoning Consideration

Ergot poisoning was initially considered, but this theory was discounted due to England’s lower prevalence of rye, the main source of ergotism, compared to the rest of Europe.

Hantavirus Connection

Research points to similarities between symptoms of the sweating sickness and hantavirus pulmonary syndrome. Some researchers propose an unidentified hantavirus as the potential culprit. Hantaviruses are zoonotic diseases carried by bats, rodents, and insectivores. Notably, both the English sweating sickness and hantaviruses exhibit similar trends, including seasonal occurrences and fluctuations multiple times a year. This leads to the possibility of the sweating sickness being rodent-borne. However, critiques of this hypothesis emerge, such as the discrepancy in the disappearance of modern-day hantaviruses compared to the sweating sickness.

Anthrax Outbreak Speculation

In 2004, microbiologist Edward McSweegan proposed a novel theory suggesting anthrax poisoning as the cause of the sweating sickness outbreak. He theorized that victims could have been exposed to anthrax spores present in raw wool or infected animal carcasses. He even suggested exhuming victims for testing to explore this hypothesis further.

Challenges in Unraveling the Origin

Despite numerous attempts, the exact origin of the disease has eluded scientists. Efforts to pinpoint the cause using molecular biology techniques have been unsuccessful due to a lack of traceable DNA or RNA.

Epidemiology of Sweating Sickness

Arthur, Prince of Wales, who may have died of the sweating sickness in 1502, aged fifteen

Arthur, Prince of Wales, who may have died of the sweating sickness in 1502, aged fifteen

Emergence of Sweating Sickness in the 15th Century

At the onset of Henry VII’s reign in 1485, Sweating Sickness emerged as a concerning health issue. The disease proved highly lethal, resulting in significant fatalities, particularly in certain regions. Speculation surrounds the possibility that Richard III fell ill with the sickness before the Battle of Bosworth Field. Reports indicate that the disease afflicted a substantial portion of London’s population in September 1485, shortly after Henry VII’s victorious return. By late October of the same year, the disease had claimed the lives of thousands, including prominent figures like lord mayors, aldermen, and sheriffs.

The appearance of Sweating Sickness triggered widespread superstition and fear. The Battle of Bosworth Field marked the end of the Wars of the Roses, with Henry VII’s ascension to the throne. Amid the ensuing chaos, grief, and anger, the search for a scapegoat commenced, and many believed the plague was a divine punishment for supporting Henry VII’s rule.

Distinguished by its rapid and deadly progression, Sweating Sickness was distinct from other known epidemics, including the Black Death and pestilential fever. The illness earned its name due to the profuse sweating it induced. The disease’s impact extended to Ireland in 1492, as documented in the Annals of Ulster, noting the death of James Fleming, 7th Baron Slane, from the “perspiring plague.” The Annals of Connacht and the Annals of the Four Masters also referenced this outbreak, describing a peculiar 24-hour episode of the illness. Notably, infants and young children remained relatively untouched by the disease. Chronicler Richard Grafton recounted the Sweating Sickness outbreak of 1485 in his work, mentioning the prescribed treatment of bed rest, fasting, and limited water intake throughout the 24-hour duration of the illness.

16th Century Outbreaks
Title of a publication in Marburg, 1529, about the English Sweating sickness

Title of a publication in Marburg, 1529, about the English Sweating sickness

In 1529, a publication in Marburg highlighted the English Sweating sickness, a mysterious ailment that made its presence known in the 16th century. Notably, there was no record of the illness between 1492 and 1502. During this time, a possible occurrence of the sickness affected Arthur, Prince of Wales, and his wife Catherine of Aragon in March 1502. Their affliction was described as arising from “a malign vapour which proceeded from the air.” Despite investigations into Arthur’s death in 2002, the exact cause remained elusive. Catherine recovered, but Arthur passed away on April 2, 1502, just six months before his sixteenth birthday.

Following the initial appearance, the English Sweating sickness resurfaced in later years. In 1507, a second outbreak occurred, followed by a more severe epidemic in 1517. Notably, this disease showed a strong preference for affecting the English population, with foreign visitors experiencing fewer cases. Even in 1528, an outbreak in Calais, an English territory, did not spread into France. The fourth outbreak, also in 1528, reached epidemic proportions. Starting in London, it spread across England, excluding the far north. Scotland was spared, but Ireland saw cases, including prominent figures like Lord Chancellor Hugh Inge. The mortality rate was particularly high in London, leading Henry VIII to change his residence.

In 1529, the disease affected even the closest associates of Henry VIII. Thomas Cromwell lost his wife and daughters, while Anne Boleyn, Henry’s mistress, was believed to have contracted the illness. Cardinal Wolsey also fell victim but survived.

The English Sweating sickness transcended borders, suddenly appearing in Hamburg and swiftly causing over a thousand deaths. It spread through eastern Europe, including Denmark, Sweden, Lithuania, Poland, and Russia. Notably, Italy and France remained largely unaffected except in the English-controlled Pale of Calais. The disease emerged in Flanders and the Netherlands, possibly introduced by travelers from England. In 1529, it appeared simultaneously in Antwerp and Amsterdam, lingering for a short duration. However, by year-end, it vanished across mainland Europe, except for a lingering presence in eastern Switzerland before disappearing entirely.

Final Epidemic and Its Spread

The last significant occurrence of the disease took place in England in the year 1551. Although evidence from burial practices in smaller European towns hints at the potential existence of the disease in other regions prior to this outbreak, historical records pinpoint the start of the outbreak to Shrewsbury in April of that year. The disease swiftly claimed about 1,000 lives in Shrewsbury before rapidly extending its grip across the entire nation of England, only to significantly subside by the time October arrived.

Demographics and Impact

Curiously, the disease exhibited a higher prevalence among younger men in comparison to other demographic groups, possibly attributed to their increased social interactions. This observation suggests that social exposure might have played a role in the spread of the disease within this particular segment of the population.

Eyewitness Accounts and Records

One of the contemporaries who documented the outbreak was John Caius, whose firsthand narrative titled “A Boke or Counseill Against the Disease Commonly Called the Sweate, or Sweatyng Sicknesse” offers insights into the dire situation. Another account comes from Henry Machin, who chronicled the outbreak in his diary. His entry from July 7 reveals the emergence of a new “swet” in London and describes how the disease affected both the common people and prominent figures, including young dukes.

Other Local Outbreaks

The year 1551 also saw an outbreak in Halifax Parish, where 44 deaths were documented. Another outbreak referred to as the ‘sweating sickness’ occurred in Tiverton, Devon, in 1644. This outbreak, recorded by Martin Dunsford in his History, resulted in the deaths of 443 individuals, with 105 burials occurring in October. Notably, these occurrences lack detailed medical descriptions, and the Tiverton outbreak occurred well after the generally recognized disappearance of the ‘sweating sickness’ in 1551.

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  • Heyman, P., Simons, L., & Cochez, C. (2014). Were the English Sweating Sickness and the Picardy Sweat Caused by Hantaviruses? Viruses6(1), 151–171.‌

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