<human>:  When did Santa Claus first appear?
<bot>: The first known appearance of Santa Claus was in the poem The Night Before Christmas in 1823. The poem was written by Clement Clarke Moore. It tells the story of a man named Kris Kringle who brings gifts to children on Christmas Eve. The poem was written as a letter to his son, so it was not intended to be a factual account of how Santa Claus came to be.