Many fictional holiday characters have origins rooted in actual history. Santa Claus, for example, is based loosely on a bishop named St. Nicholas known for giving anonymous gifts in a town in present-day Turkey. But what about Santa's trusty sidekick, Rudolph the Red-Nosed Reindeer? When did Santa start flying around the globe with a team of magical reindeer, and is there some epic Christmas Eve fog in the history books?
Rudolph the Red-Nosed Reindeer, a fairly new addition to Christmas lore, made his debut in 1939 as a promotional stunt for the Chicago-based department store Montgomery Ward. For years, the store had been buying and giving away Christmas-themed coloring books, but realized it could save a few bucks by making them in-house. So they asked Robert L. May, a 34-year-old copywriter, to create a holiday story specifically for their customers. May produced Rudolph, "the rollinckingest, rip-roaringest, riot-provokingest, Christmas give-away your town has ever seen!... A laugh and a thrill for every boy and girl in your town (and for their parents, too!)" May considered other names for his leading character, including Rodney, Rollo, Reginald, and Romeo (can you imagine Rodney the Red-Nosed Reindeer?), but eventually settled on Rudolph.

May's coloring book enjoyed instant success. The company gave away some 2 million copies in the first year. By comparison, only 430,000 copies of John Steinbeck's The Grapes of Wrath, a bestseller also published in 1939, were printed in its first year. The next year, Montgomery Ward began selling Rudolph-themed items and, later, May's brother-in-law wrote a song to accompany the book, which Gene Autry recorded in 1949. It remains the second-best selling Christmas song of all time. In the song, and later, the 1964 stop-animation TV special, Rudolph is an established, if bullied, member of Santa's reindeer family up at the North Pole before the fateful ride. In the book, however, Santa stumbles upon Rudolph for the first time when delivering gifts to his home one foggy Christmas eve — and drafts him as a navigation aid. "And you," Santa says in the book, "May yet save the day! Your wonderful forehead may yet pave the way!"
But when did Santa start hitching rides with reindeer? That piece of fiction can be traced back to 1823, when Clement C. Moore wrote the poem known today as The Night Before Christmas. Back then, it was called A Visit from St. Nicholas, and it told of Santa's "eight tiny rein-deer." (Fun fact: Donner and Blitzen, whose names translate to Thunder and Lightning, were originally called Dunder and Blixem.)
Today, Rudolph the Red-Nosed Reindeer remains a staple in American Christmas tradition. The 1964 production is the longest-running television special ever, and, with rapper DMX's recent rendition of the song, it's safe to say Rudolph will long be a permanent part of our pop culture lexicon.