The American idea of Santa Claus largely comes from a poem called "A Visit from St. Nicholas." Clement Clarke Moore wrote the poem in 1822, but he did not put his name on it. Some say it is the most famous poem ever written by an American.
The poem, also known as "’Twas the Night Before Christmas," tells the story of the arrival of Santa Claus. On the night before Christmas, a man hears noises outside his house. He looks outside and sees Santa Claus, who is also is called Saint Nicholas. Santa is flying on a sleigh pulled by eight reindeer. The sleigh lands on the roof of the storyteller’s house. Santa enters the house through the chimney, carrying a sack full of toys. He puts toys in the stockings, which are hanging by the fireplace. The storyteller laughs as Santa and the reindeer fly away.