The Pied Piper of Hamelin is the subject of a legend from the town of Hamelin, Lower Saxony, Germany, in the Middle Ages. The earliest references describe a piper, dressed in multicolored clothing, who was a rat-catcher hired by the town to lure rats away with his magic pipe. But then the citizens refuse to pay for this service, and he retaliates by using his instrument's magic power on their children, leading them away like he did with the rats.
This version of the tale is beautifully illustrated by Kate Greenaway.