Prior to Tolkien, fantasy writing was sparse. At least, what we think of now as fantasy was sparse. Because of that, Tolkien is widely considered the "Father of Modern Fantasy" or, specifically, the "Father of High Fantasy." Along with the title has come the assumption that it was Tolkien who established our model of how fantasy ought to be written, that it was Tolkien who originated the tropes. People, often people who have not read The Lord of the Rings, look at what Tolkien did and ascribe the origins of all that fantasy has become to him.
Now, I love The Lord of the Rings. The Hobbit, as you'll know if you've checked out my "Of Significance..." page on my own StrangePegs blog, is one of the three books that I think everyone should read. And I don't undervalue Tolkien's importance. There would be no fantasy genre as we know it today without him. However, I don't think that we can "blame" Tolkien for today's fantasy tropes. In fact, many of the things we think he did, he did not, in fact, do. No, for the origins of fantasy, we have to look elsewhere.
And we will. But not today. Before we get to that, we need to figure out what are the key elements of fantasy literature, and these tend to hold true whether it's high (epic) fantasy or not.
With that in mind, I've come up with a list. This is my list, mind you, because I couldn't find anything that resembled a definitive list or even lists with many things in common. I'm just going off of the fantasy I've read (which is a lot) and the things I've found in common amongst them.
1. The protagonist (I'm just going to say "hero" from here on out; it's shorter) is not an adult (and usually male).
2. The hero is an orphan (usually both parents are dead, although there is sometime one (usually the mother)).
3. The hero is "special" in some way.
4. There is a prophecy, generally related to the hero.
5. There is an old mentor of some sort, usually a male. (We recognize this character as "the wizard.")
6. There is a quest of some sort involved that only the hero can complete.
7. There is some kind of descent
8. The hero has companions who help him on his journey.
9. There is some sort of "dark lord" who can only be defeated by the hero.
10. There's an absence of technology.
These are the ones that come to mind as being part of the general "fantasy ideal." I could include other things like:
There are other races like elves and leprechauns.
The setting is generally medieval.
Magic of some sort is involved.
But these things seem to me to be decorations for the story, not actually necessary to the functioning of it, so I'm not including them on the list (unless you can convince me otherwise), although I'm sure I'll talk about them as we go along.
Speaking of convincing, I'm not trying to say this is a definitive list, just the list I'm going to work with in looking at the origins of fantasy and, when I say "origins," I actually mean the blueprint that we use as the basis for modern fantasy writing. If you have other things that you feel are essential, please let me know what they are, and I'll look at them.
Oh, and just to be clear, I'm not dealing with any sub-genres like paranormal or vampire or anything like that. Even though those often use these same basic "rules," they have their own twist on them.