The poem beginning, “Twas the night before Christmas…,” is titled A Visit from St. Nicholas, and was written in 1823 by Clement Clarke Moore. This poem largely standardized St. Nicholas as a fat man who flew around with reindeer.
It is quite remarkable that this caught on. It almost seems like Clement Clarke Moore combined all of the weirdest things he could possible imagine and created an image of Santa.
It appears one night of aggressive moonshine binging gave us the endearing image we celebrate today!