On December 23, 1823, the Troy Sentinel, a small newspaper in upstate New York, printed a poem under the title “Account of a Visit from St. Nicholas.” It had no author’s name. The editor introduced it with a short note wishing the paper’s young readers a merry Christmas and saying he did not know who had written it.

The poem begins “‘Twas the night before Christmas, when all through the house / Not a creature was stirring, not even a mouse.” A father, woken by a noise, looks out of his window to see a miniature sleigh drawn by eight tiny reindeer, which he names one by one. Saint Nicholas comes down the chimney, “a right jolly old elf,” with a twinkle in his eye and a pipe in his teeth, fills the stockings without a word, lays a finger beside his nose, and rises back up the chimney.

Before this poem, the gift-bringer of the Dutch and English traditions was a stern figure, often a bishop, who came on his own feast day in early December and was as likely to punish as to reward. The poem made him small, round and merry, moved his visit to Christmas Eve, gave him a sleigh and reindeer, and sent him down the chimney. Newspapers reprinted it year after year, and the Santa Claus of American Christmas grew from it.

In 1837 the poem was credited in print to Clement Clarke Moore, a scholar who taught Hebrew and Greek at a seminary in New York, and in 1844 he included it in a book of his poems. The usual story is that he made it up for his children, and that a family friend sent it to the newspaper without his knowledge. But descendants of another New Yorker, Henry Livingston Jr., who died in 1828, have long claimed that he wrote it, and some scholars agree with them. The question has never been settled.

The reindeer have changed a little. In the first printing, the last two were Dunder and Blixem, Dutch for thunder and lightning. Over the years they became Donder and Blitzen.