Before this poem, there was no universally agreed-upon Santa Claus — no sleigh, no eight reindeer called by name, no chimney entrance, no jolly old elf with a round belly that shakes like a bowl full of jelly. Clement Clarke Moore wrote it for his own children in 1823, and within a few decades it had quietly become the template every other Santa Claus story, image, and tradition was built on.Short enough to read aloud in one sitting on Christmas Eve, and still the poem most people are actually quoting when they talk about "the night before Christmas" — even if they've never read the original.