Ever wonder why a fat guy named Santa Claus, with a workshop on the North Pole wherein elves make toys, brings gifts to children all around the world on Christmas using a reindeer-powered sleigh? Well I'm glad you asked.
The historical predecessors of the Anglo-American version of Santa Claus (and Christmas folklore overall) are a real historical figure – St. Nicholas of Myra – and character from Dutch folklore named Sinterklaas. Catholic veneration of St. Nicholas emphasized his famous generosity toward the poor, not merely feeding and clothing them but giving them gifts. Sinterklaas was a mythical winter figure in German-speaking Europe dating back to the Dark Ages (with many characteristics of his appearance borrowed from Odin). Eventually the legend of Sinterklaas became intertwined with St. Nicholas, whose similar background – both were Bishops famously generous with gifts – resulted in Sinterklaas making a tradition of bringing gifts on St. Nick's feast day (December 6). So why haven't we exchanged gifts already?
Enter a similar character in British folklore, Father Christmas. Daddy C was a rotund, white-bearded older man with a green robe who symbolized the spirit of Christmas in a secular sense. It is worth noting that Christmas, from a religious perspective, was considered a very minor holiday until…well, we'll get there in a minute. But for the latter half of the 18th Century and the dawn of the 19th, the London Times on Dec. 25 only bothered mentioning Christmas about half the time. It just wasn't a big deal.
The people who made Santa Claus as we know him today are largely the same people who made Christmas as we know it: Charles Dickens in Britain and little-known Clement Clarke Moore in the United States (Washington Irving had created an "American" Santa in 1808 – a fat Dutch sailor – tongue in cheek as a way to mock the Dutch, so that doesn't quite count). Of course you know Dickens, although you might not realize how instrumental A Christmas Carol was in making Christmas a major cultural holiday in Britain. You don't necessarily know CC Moore, but a poem he wrote for his children, published at the urging of his friends and family in 1823, is well known. "A Visit from Saint Nicholas" begins:
Twas the night before Christmas, when all through the house
Not a creature was stirring, not even a mouse;
The stockings were hung by the chimney with care,
In hopes that St. Nicholas soon would be there;
The children were nestled all snug in their beds,
While visions of sugar plums danced in their heads,
This poem created and established 99% of what we "know" about Santa Claus today – the sleigh pulled by 9 reindeer (which Moore named), landing on the roof and entering down the chimney, and the sack of toys made in his workshop. Moore used the name St. Nicholas, but the character he created was essentially an amalgam of Father Christmas (who was responsible for moving the gifting from St. Nicholas' feast day to Dec. 24), St. Nicholas, and Sinterklaas.
Before Moore and Dickens, images of Santa Claus existed but varied considerably by region. These authors began the process of standardizing the character and his narrative. Appearance-wise, Santa also began to take on a single recognizable form. He wore a robe like Father Christmas, but it was red (the color of Sinterklaas' bishop's robes) instead of green. He had a big white beard and a large belly like both the Sinterklaas and Father Christmas characters before him, as this appearance was considered to make him more "jolly." Political cartoonist Thomas Nast's depictions of Santa in this form cemented the image and it has varied little since the mid-19th Century (Nast also created, in 1886, the idea of a workshop on the North Pole. No one is quite sure where the idea of elves originated.)
The idea that Santa was created by the Coca-Cola company is an urban legend, although early 20th Century Coke advertising certainly did popularize the character even more. The fact that he wore Coke colors didn't hurt.
Finally, in the 1930s, Montgomery Ward gave away millions of coloring books to children every year as a promotion, so they tasked one of their advertising copywriters, Robert May, with creating their own coloring book. They saw this as a cheaper alternative to buying coloring books from vendors. He created the story of "Rudolph the Red-Nosed Reindeer" based on the reindeer in Moore's poem. The coloring book was wildly popular and May's brother wrote a song based on its story, recorded in 1939 by Gene Autry and immediately becoming a mega-hit. The stop-motion animated Rudolph TV special created in 1964 elaborated the story considerably but retained most elements of May's original storyline.
If you ever win money at trivia or on a game show for knowing any of this, I get 10% off the top. That means before taxes, people.