From Wikipedia:
Another legend tells how a terrible famine struck the island and a malicious butcher lured three little children into his house, only to kill and slaughter them and put their remains in a barrel to cure, planning to sell them off as ham. Saint Nicholas, visiting the region to care for the hungry, not only saw through the butcher's horrific crime but also managed to resurrect the three boys from the barrel. Another version of this story, possibly formed around the eleventh century, claims that they were instead three clerks who wished to stay the night. The man murdered them, and was advised by his wife to dispose of them by turning them into meat pies. The Saint saw through this and brought the men back to life. This alternate version is thought to be the origin of the English horror legend, Sweeney Todd.