Medieval Europe knew plague well. What reached England in the late summer of 1485 was something else: a fever with a sudden onset, a drenching sweat and a death rate that could be measured in hours. It came back four more times and then stopped. No one has ever shown what it was.
The Horror
The first confirmed outbreak fell in 1485, within weeks of Henry VII arriving in London at the end of August. The disease reached the city on 19 September and, by late October, had killed several thousand people there. An earlier outbreak at York in June is possible, but the symptoms were not adequately recorded to say. The sickness returned in 1507 or 1508 (the sources do not agree on which), in 1517, in 1528 and finally in 1551.
The best description comes from the physician John Caius, so much of what is said about the symptoms rests on one observer. The illness began with apprehension and cold shivers, with dizziness, headache and pain in the neck, shoulders and limbs. A hot, sweating stage followed, with delirium, a racing pulse, intense thirst and pain around the heart. No rash was noted. Death or recovery often came within eight to ten hours, and the whole illness usually lasted about a day.
The 1528 outbreak began in London in late May and spread across England and into Ireland, though not Scotland. Henry VIII broke up his court and moved from house to house to avoid it. Physicians believed Anne Boleyn had caught it, and she survived. In July 1529 the disease reached Hamburg by ship, and by the end of that year had passed through the Baltic, southern Germany, Antwerp and Amsterdam. It had vanished from mainland Europe within months. The last outbreak began at Shrewsbury in April 1551 and killed about a thousand people there. It had nearly disappeared by October, and was never recorded again as the same disease.
What is not settled
Popular accounts say that the Sweat killed the rich and spared the poor, and that it singled out the English abroad. Neither claim is firm. The surviving accounts suggest that rural and working people were heavily affected as well as the elite, and that recorded mortality was highest among men in their thirties and forties. In 1551 the victims were more often young men, possibly because of how much they mixed in society. Infants and young children were reportedly not affected in 1485. The belief that the disease “followed” the English is a contemporary impression, not a measured fact.
The claim that Prince Arthur died of the Sweat at Ludlow in April 1502 is also uncertain. His illness may have been the sweating sickness, but a 2002 examination of his tomb could not determine what killed him. The figure of 15,000 dead in six weeks in 1485, repeated in popular retellings, is unconfirmed.
The Modern Relic
There is no known body, no tissue sample and no preserved pathogen. Attempts to find the pathogen’s DNA or RNA have failed for lack of usable material. Proposals include an unknown hantavirus, anthrax, influenza and relapsing fever, and each has objections: hantaviruses are not generally passed from person to person, for example. None is proven.
What survives is paper: Caius’s description, city records, and the letters of a court that kept moving. The Sweat is a rare epidemic with a start date, an end date and no name for its cause.
