Something did happen to the children of Hamelin in 1284. Exactly what, no one knows.
https://www.ancient-origins.net/myths-legends/pied-piper-hamelin-001969
Robert Browning put the story down in a poem – one my mother learned at school and would recite to us. Her favourite lines were:
“’Tis clear,” cried they, “our Mayor’s a noddy;
And as for our Corporation – shocking
To think we buy gowns lined with ermine
For dolts that can’t or won’t determine
What’s best to rid us of our vermin!”
And why was it her favourite? Well, because she got to bang on the table for emphasis.
Time Travelling With Kids 