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.