I believe the closest ancestor (?) to Santa Claus comes from the Dutch Sinter Klaas. You'll see a lot of similarities between the American Santa and the older Dutch Sinter Klaas... of course there are also some very important differences. Notably the parts having to do with Santa's helpers, and coming from Spain as opposed to the North Pole. The US Santa is also a pushover for presents. He doesn't quite have the same set of systemic punishments that other Saint Nicolas stories seem to have for misbehaving children.
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