In Holland in the 16th century the whole country got apparently sick for no reason just out of fear from a rumor that there was a sickness spreading.
The dutch are something special I must say, some of the most interesting stories you can hear about them, not to mention their urgency to keep telling you about what folk sayings they have.
Not to mention of how veritable are stories from 1500s (16th century) when superstition was still a thing anywhere on the planet and owning slaves was a thing.