Elves form an integral part of contemporary high fantasy and have done so since the days of Tolkien, who first included them as a key race on the side of good in The Hobbit and the Lord of the Rings series. Most, if not all, contemporary depictions of the elves owe much to Tolkien's works. And these contemporary depictions are present in various media, from literature, tabletop games, and even videogames.
J. R. R. Tolkien, as much as he popularized elves in modern fantasy, did not actually "invent" them. The word "elf" itself is a word inherited from the Germanic past of English, from the Old English word ælf/ælfe, which itself is cognate with Old Norse alfr/alfar. And it is largely from the literature from these two languages that most later understandings of elves developed and are derived.
The elves find a place in Nordic-Germanic myths and legends as a race of beings who are immensely more graceful, beautiful, and dextrous than humans, characteristics that tend to survive to contemporary depictions. The elves in Norse mythology are also ruled over by the god Freyr, one of the most important deities of their pantheon.
The god Freyr
Freyr was the ás (god) associated with sacred kingship who through his hamingja ("luck"; in this case, his divine power) was also responsible for virility, prosperity, and fertility. His real name, however, was not Freyr. Freyr is, in reality, his title, coming from Proto-Norse *frawjaz, meaning "lord", which referred to his function.
His true name was Yngvi, often combined with his title to form the compound Yngvifreyr, or "Lord Freyr". As stated earlier, his association was with sacral kingship, and he was probably considered the ancestor of the Ingvaeonic Germanic tribes who lived in what is now Denmark, Frisia and the Netherlands, as well as, importantly, the progenitor of the legendary Yngling royal dynasty of Sweden from whom the first dynasty of Norwegian kings claimed descent, through which they shared in his hamingja which is passed down the family line.
So where does this connect to Tolkien's elves? Their history is given in the book of Middle-earth religion and history, The Silmarillion. Well, the Vanyar, who are, in a sense, the "high elves", in that they descend from the first "patriarch" of the elves, were, in the period of migration to Valinor, home of the Valar (the gods of Middle-earth, akin, perhaps to the Old Norse Vanir of whom Freyr was a member?) which lay in the West, led by an ambassador sent from their Kindred, Ingwë, who later became their king and the high king of all elves as they settled down at the foot of the mountain that was the home of Manwë, head of the Valar. Interestingly, in the language of the "High Elves", Quenya, King Ingwë's name might not be a proper name as such, but a title, which means "chief",–much as Freyr means "lord". His full title was Ingwë Ingweron; the "Chief of the Chieftains"
Ingwë High-King of All Elven-Kindred.
This migration to the west may also reflect the Germanic migration period which led to the Proto-Germanics entering Central and Northern Europe and breaking up into several disparate groups, like the Ingvaeones. Tolkien, who was well-versed in Eddaic lore would have been familiar with the god Yngvi Freyr who had dominion over the elves, and probably, like many other things in his stories (such as the name for his world, Middle-earth, which corresponds to the ON Midgardr) based at least the Kindred of the Vanyar and their leader on the elves of Germanic myth and their god-king.
