The children of North America have a new Christmas tradition: The elf on the shelf.
Alternatively panned as creepy and adored as a fun holiday ritual, the trademarked Elf on the Shelf dates back to 2005, when author Carol Aebersold self-published a tale of a little elf sent by Santa to report on children's behavior leading up to Christmas. A toy elf sold with Aebersold's book plays that role in thousands of homes around the country.
It's a strange place to end up for these Christmas-y little creatures, who once stood side by side with Norse gods and took the blame for inexplicable illnesses in medieval Europe. But elves stand the test of time, playing modern-day roles in J.R.R. Tolkien's "Lord of the Rings" series as well as acting as Santa's spy agents. [Photos of 'Middle Earth': New Zealand's Fantasy Landscape]
Here's how these little people have evolved.
The origin of elves
Ancient Norse mythology refers to the álfar, also known as huldufólk, or "hidden folk." However, it's risky to translate álfar directly to the English word "elf," said Terry Gunnell, a folklorist at the University of Iceland. Elves are thought of as little people, perhaps wearing stocking caps and cavorting with fairies, but the original conception of álfar was far less whimsical.
Some ancient poems place them side by side with the Norse gods, perhaps as another word for the Vanir, a group of gods associated with fertility, or perhaps as their own godly race. It's likely, Gunnell said, that elves' inventors had no single, unified theory on elvish identity; rather, there were a variety of related folk beliefs regarding this unseen race.
"They look like us, they live like us -- at least in the older materials -- and probably, nowadays, if they're living anywhere, they're living between floors in flats ," Gunnell told LiveScience, referring to the notion of an invisible, parallel world inhabited by álfar — the friendly neighbors who live between the seventh and eighth floors.
Iceland was settled in the 800s by Scandinavians and Celts, brought from Ireland as slaves. Both Scandinavian and Celtic cultures had myths of fairies, elves and nature spirits, which began to meld into the concept of álfar as representatives of the landscape, Gunnell said. Iceland's eerie, volcanic setting probably played into these myths, Gunnell said, especially in the dark of winter, when the Northern Lights are the only thing illuminating the long nights.
"The land is alive, and really, the hidden people are a personification of a very living landscape that you have to show respect for, that you can't really defeat," Gunnell said. "You have to work with it." [Top 10 Beasts and Dragons: How Reality Made Myth]
Scandinavians and Celts weren't the only Europeans who used unseen, supernatural species as symbols of the wilds surrounding them. Farther south, Germans believed in dwarves and little sprites called kobolds. Scots had house spirits called brownies.
Elves became part of this mythological mix throughout the first millennium A.D., according to Alaric Hall, a lecturer at the University of Leeds who penned an entry on elves for the upcoming "Ashgate Encyclopedia of Literary and Cinematic Monsters" (Ashgate, 2014). The word "elf" derives from the ancestor language of German, English and today's Scandinavian languages, Hall wrote, and the first written references to them come from church texts starting around A.D. 500.
Medieval Europeans saw elves as dark and dangerous, and linked them to demons. In the Old English "Beowulf," which dates to sometime between A.D. 700 and 1000, elves get a mention as an evil race that descended from Cain, the biblical son of Adam and Eve who murdered his brother:
"Of Cain awoke all that woful breed,
Etins and elves and evil-spirits,
as well as the giants that warred with God."