Written accounts of mass hysteria come from all over the world and date back to the Middle Ages at least. They involve mostly women but not solely, people of all ages, and occur in a variety of settings. Often the backdrop is an institution that imposes rigid moral and behavioral codes on its residents, such as a boarding school or convent.

One of the odder accounts is about a seemingly contagious bout of meowing — like a cat — at a convent in France. The first person to document the episode was German physician and writer Justus Friedrich Carl Hecker. (All other accounts seem to spring from his.)

In The Epidemics of the Middle Ages, 1844, he writes:

“I have read in a good medical work that a nun, in a very large convent in France, began to mew like a cat; shortly afterwards other nuns also mewed. At last all the nuns mewed together every day at a certain time for several hours together. The whole surrounding Christian neighbourhood heard, with equal chagrin and astonishment, this daily cat-concert…”

Eventually, probably prodded by complaining convent neighbors, police placed a bunch of soldiers at the convent’s entrance. The nuns were told the soldiers had rods “and would continue whipping them until they promised not to mew anymore.” Which apparently did the trick.

While meowing as a form of release or resistance or whatever is plain bizarre to us, context matters. As American medical sociologist Robert Bartholomew has pointed out, once upon a time many people believed in and terribly feared demons and possession — including possession by animals as familiars. Cats still are a receptacle for our superstitions, imagine how potent that fear might have been in the Middle Ages.

Bartholomew and author Simon Wessely shed other light as well, on the emotional and spiritual deprivation these early nuns suffered. Many were sent by their families to the convent rather than answering a call to serve Jesus. “Young girls typically were coerced by elders into joining these socially isolating religious orders,” the two men write, “practising rigid discipline in confined, all-female living quarters. Their plight included forced vows of chastity and poverty. Many endured bland near-starvation diets, repetitious prayer rituals and lengthy fasting intervals. Punishment for even minor transgression included flogging and incarceration.”

The case of the meowing nuns is one of many historical accounts of sisters behaving in remarkable ways. There’s biting nuns, barking nuns, profanity-spewing, rolling-around-in-the-muck naked nuns — you get the idea. But whose to say how any of us would respond to such an impossible life? Convents in the Middle Ages could be places of learning for girls and women. Prayer and community can bring joy. But if you are a young woman forced into a life of poverty, chastity, dusk-to-dawn labor — all under the unbreakable seal of a lifetime vow — you might meow or bark or scream like a leg-trapped animal, too.