Epidemics, by their very nature, come and go. The dramatic 16th-century series The Tudors and Wolf Hall have renewed interest in the long-gone “English sweating sickness,” an obscure but deadly malady whose origins are still debated. In our own era of rapidly emerging disease and epidemics (West Nile, SARS, Ebola, Zika, etc.) the historic study of such outbreaks isn’t just an academic exercise. It can’t actually be said, after all, that that ancient disease was vanquished forever.

There were five English epidemics of sudor anglicus, as it was known in Latin, between 1485 and 1551. These were summer outbreaks with high mortality; people died within a few hours of being stricken. Paul R. Hunter details what’s known of the clinical features of the disease and its possible pathogenesis. He favors an enterovirus, but its “exact causative agent remains unknown.” More recent studies cited by John F. Flood suggest a hantavirus with a rodent-human connection. Climate may have played a role—unusually warm and wet springs can mean lots of mammalian hosts for such viruses.

As Flood notes, there were some famous survivors, including Cardinal Wolsey, Erasmus (on a visit to London), and Anne Boleyn. A notable characteristic of the sickness was that royal households and academic institutions—the wealthy, young, and strong—were hard hit. A vernacular name for the malady was “stopgallant” because it stopped so many young gallants. Even dukes, bishops, and mayors were struck down. Monasteries were particularly vulnerable, although by the 1551 outbreak this was no longer the case because the monasteries had been dissolved by then. Hunter suggests the poor may have had a secret weapon—exposed to more diseases from childhood then the well-off, those poor who managed to survive childhood had stronger immune systems.

Flood also explores the fear the disease aroused on the continent when it ravaged the German states, crossing into Switzerland and as far as Russia in 1529. Flood highlights this notable difference between English and German physicians—in England, nothing was published about the disease until 1552, while in Germany, numerous warnings, cures, and discussions about it were published in the midst of the 1529 epidemic. He attributes this to the Reformation. For more than a decade already, a “well-established book trade had been fully accustomed to addressing the burning issues of the day.”

Information remains one of the most important weapons in the battle against epidemics. Knowing the history of past outbreaks helps us arm against future ones. Since science never quite pinpointed the cause of this epidemic, as Flood notes, “though the disease has not been seen in England for such a long time, there is no saying that it will not be back!”