From 1485 through the latter part of the 16th century, a new plague – English "sweating sickness" – ravaged England and Europe, killing thousands of people. The fearsome disease had many names including, "Sudor Anglicus," "English Sweat," "the Sweat," "the Swat," "the New Acquaintance," and “Stoupe! Knave and know thy master." The dreaded sweat, which took its victims in fewer than 24 hours, was more or less localized in England, but it made its way to the European Continent in 1528.
The symptoms of sweating sickness not only confused contemporary medical practitioners but their cause also remains a mystery. And, of course, like the dreaded Black Death, sweating sickness was terrifying, deadly, and really, really unpleasant.
At the Battle of Bosworth Field in August 1485, Thomas, Lord Stanley pulled back his support for the Tudor cause on account of "sweating sickness." Thought at the time to be more about Lord Stanley's shifting loyalties than an actual ailment, the disease was present six weeks later in London, perhaps thanks to Henry's victorious troops and their triumphant return to the city.
Deaths from "sweating sickness" were reported in London in mid-September 1485, and records indicate it continued to kill through October. Thomas Forrestier, a French doctor in London, explained that the "sickness cometh with a grete swetyng and stynkyng, with rednesse of the face and of all the body, and a contynual thurst, with a grete hete and hedache because of the fumes and venoms.”
By the end of October 1485, English Sweating Sickness had killed 15,000 people in London.
The populations most affected by "sweating sickness" were of higher social classes in England, another confusing aspect of the disease. London lost two lord mayors, three sheriffs, and six aldermen in 1485 alone. There are also no accounts of young children suffering from English "sweating sickness," and it seems to have avoided the elderly as well, which is most uncommon for an epidemic.
When Arthur, Prince of Wales, died in 1502, it may have been from English "sweating sickness," and several members of Henry VIII's court took ill during the 16th century. The King was paranoid that he would get sick too. In 1529, "one of the filles de chambre of Mlle Boleyn was attacked on Tuesday by the sweating sickness. The King left in great haste, and went a dozen miles off... This disease is the easiest in the world to die of." Anne Boleyn mentioned the "sweat" in a letter to Thomas Wolsey after his bout with the disease, as well.
After its initial appearance in England in 1485, "sweating sickness" showed up again in 1508 (some sources place it in 1506), 1517, 1528, and 1551. The cause of the disease was unknown – and still remains debated – and each time the epidemic struck, it killed thousands of people. The worst bout with "sweating sickness" took place in 1528, which was also the same year that it jumped the English Channel.
In 1528, English "sweating sickness" was transported to Germany by ship, leading to thousands of the deaths. In Danzig alone, 3,000 people died. It spread to Scandinavia, Poland, and parts of Russia, but it never went into France or Italy.
At the time, doctors thought the disease was a form of influenza, but modern researchers now believe it may have been the hantavirus. In 1718, a similar disease, known as the Picardy Sweat, appeared in the Picardy region of France. Historians continue to investigate whether or not they had the same cause.