I've just come across Roy Jacobsen's excellent essay on the Icelandic Sagas as the “Backbone of Nordic Literature”, and I wanted to comment on it here.
If you're not familiar with the genre, let me offer a quick and somewhat simplified overview…

Iceland was settled by Norwegians in the second half of the 9th century during a period of strife concerning the various Norwegian kings and their ambitions. The descendants of the settlers themselves claimed that this was the primary cause, but later historians point to shortages of arable land, etc.

The founding population seems to have been mixed (Scandinavian, Scottish, Irish) based on genetic evidence, but culturally the Icelanders thought of themselves primarily as Norwegian settlers, and the language they used for their writing was Old Norse, once they started writing things down.
And they had a lot to write about. They were intensely interested in history, especially family stories and genealogy, and they kept records of their own settlement's important events. (This is, in fact, where the settlement of Greenland and the brief settlement in Vinland (Newfoundland) circa 1000 AD are recorded.)
(incidentally, they were also interested in self-government and decided many issues at the Althing, the world's oldest surviving parliamentary organization. This was where outlaws were decreed, punishments determined, and — most notably — the decision was made for the entire population to convert to Christianity in 1000 AD, from the “Red Thor” to the “White Christ”, as a way of settling various religious disputes — apparently the possibility of the Christian heaven after the forgiveness of sin appealed more than the impossibility of Valhalla for non-heroes.)
The Icelandic family sagas are now available in several modern languages and you can even pick them up most of them in one volume online.
The most startling thing for first-time readers of this medieval corpus is that many of these sagas are famous as world literature, and they read as surprisingly modern novels in most ways.
All of the above is just some context, in case you are not already familiar with the genre.
Roy Jacobsen starts his essay by summarizing one story (þáttr) about the complicated adventures of Audun.
All three main characters in the story, Audun and the two kings, are characterized only by what they do and what they say, although this does not mean that we see them any less clearly. This is showing, not telling; it is realism at its best—paradoxically, in the context of a fairytale motif.
But then, that is how sagas are: paradoxical, ambiguous, classical, modern.
Roy Jacobsen
He continues…
One may ask oneself whether this is an Icelandic form of underdog literature, as one can with many of these short tales—something that illustrates the superior intelligence of the cunning inhabitants of this young, new land, measured against the pinnacles of power and intellect in the old one. One may ask whether this is a story about the little man against the powerful—a successful piece of class struggle. Or is it an example of vox populi—the wise king who listens to the voice of the people and becomes wiser still? Is it a story about trade and commerce and the intricate structures of debt and reciprocation, the significance of gifts at all levels in the hierarchy, about mental intelligence gathering through a diplomatic envoy between two warring princes? Or is it an exemplum with a miraculous Rome motif at its center?
Again, we must answer that it is all this, and much more. It is saga.
In the world of sagas, people are not one-dimensional; there is hardly any form of typecasting.
Jacobsen analyzes the story of Audun as literature (in the modern sense) vs folktale, using Vladimir Propp‘s folktale analyses as the standard.
[Does] the tale about Audun from the Western Fjords fulfil the formal requirements of a folk tale. The answer is both yes and no—and, of these answers, no is undoubtedly the most interesting and the most striking.
The story of Audun diverges from formal literature—folklore, the folk tale—on a number of significant points. In the first place, there are two and a half, if not an improvised set of dramaturgical turning points. While it follows the rule of three, the story operates just as smoothly with a rule of five or six, again apparently based on the intuition of the author, as if he was in possession of a sub-conscious golden ratio for painting a work of art with words.
The tale also has what one might call an epiphany: the sudden clarifying turnaround in the action that by later analysts was thought to define the short story, not the folk tale. Something suddenly happens that lifts the story out of the course it has been moving in until now and onto a new level. It occurs with King Harald’s line: “I wouldn’t have done that.” And Audun gives him the gold bracelet he has received from Harald’s worst enemy. These events are so full of both irony and realism that they break every mold in Propp’s relatively rigid system.
To put it another way: Audun is no Ash Lad or Numskull Jack, but a living and, we could say, a seeking and intelligent person in a realistic setting. That too constitutes a boundary between art and folklore. We are dealing with a hero who not only plays the world with his (often hidden) talents, forming it according to his own wishes and conquering it, but a hero who is both subject and object, contingent on the moods, laws and customs of existence, an integrated and complexly responsive figure in a larger whole, rather than a controller of the world.
Jacobsen then considers if the structural epiphany in the story of Audun makes it really an exemplar of the literary short story.
There is, or at least there was, a widespread orthodoxy that Boccaccio invented the short story, as it appears in his masterpiece The Decameron, written in the middle of the 14th century. But Boccaccio was not just a latecomer; he didn’t have an epiphany either, as we find it in Audun’s tale, and in so many of the other short Norse tales (þættir). We don’t find the realistic subject matter either, the ambiguity and the irony. Boccaccio is not tainted by reality, but by idyll. There is more material than structure; there is telling rather than showing, pure explanations.
So why has Boccaccio been credited with inventing the short story?
I have my own explanation: because the definition arose without knowledge of Audun and his brothers and sisters in the world of saga.
This þáttr is the first short story, to the extent that we are conscious of a first. In which case, the author of Audun’s tale is the inventor of the short story, and he invented it, let’s say the 4th March 1219, because this is a chance occurrence that strikes a writer very rarely in a lifelong career. And the inventor’s name is Snorri Sturlason.
…
In any case, Audun’s tale is certainly a short story, as Chekhov, Borges and Hemingway shaped them, to mention two authors who acknowledged their debt to saga literature. And it is also unmistakably saga.
Jacobsen then goes off and tries to tie the sagas in as predecessors of modern novels, as well, and here I think his case is weaker. He focuses on the so-called innovations of some modern authors and points to their saga antecedents. This may all be true (though the innovators weren't necessarily familiar with the icelandic saga), but it is not, I think, all that relevant.
What he misses, I believe, is one of the very definitions that distinguishes traditional tale (like Propp) from literature, and he touches upon it above, in his remark:
All three main characters in the story, Audun and the two kings, are characterized only by what they do and what they say, although this does not mean that we see them any less clearly. This is showing, not telling; it is realism at its best
The interiority of a character's thoughts are very much a feature of modern literature. The ballad, the saga, the epic — they show you what a character does and what he says. They don't dwell on what he thinks, his internal analysis of his own motives, nor do they try to explain those motives by other means. They assume that the hearer of the story understands the character by what he does.
Does anyone have difficulty understanding Achilles in the Iliad? The fatal actions of the lovers in Little Musgrave? The schemes of the Coyote in the Roadrunner cartoons? No one needs to explain these characters, since it is their words and deeds that do that for us. And if that's not good enough (e.g., the enigmatic Roadrunner), the mystery is left deliberately unexplained, for us to wonder about.
It is difficult, however, to point to this in modern literature. The “show, don't tell” recommendation for writing fiction is based more on increasing vividness by having characters carry the story and not relying on intrusive authorial explanation. But modern literature is full of characters who explain themselves for the benefit of the reader, who tell the reader all too much about what they are thinking and doing and why, as a way of engaging the reader's understanding.
We didn't use to find that necessary.
Look at drama as a narrative form, and think how modern it feels for a character to tell the audience directly what he wants and feels and plans to do, and why. Compare that to, say, the work of a mime or of mummers, where words aren't an option, much less interior thoughts. Compare that to the Roadrunner cartoons which are essentially wordless but carry stories that are perfectly clear to any child.
The Icelandic family sagas are a form of traditional literature, despite being in prose (vs oral-formulaic epic verse form), with the pre-modern taste for letting characters demonstrate what they are rather than telling us. They have almost seamlessly influenced modern literature in some ways, and we can read them easily today despite our modern tastes, but their focus is more on what situations make people do, what they make people reveal about themselves, and less about letting us into the interior thoughts of their characters. In particular, they instantiate a world which considers people to be relatively immutable — that they are what they are — and as such we understand them and why they behave as they do without needing their interior justifications.
And this is definitely a pagan point of view (despite Iceland's conversion), not one sympathetic to change and redemption. Our universal comprehension of mime tells us that we think in terms of archetypes, character-types, stock characters. They are our first-order interpretation of social reality. Redemptive religious perspectives are definitely later grafts onto the old stock, and a much more fragile growth.
Characters have to tell us what they think if they want to have any hope of convincing us that they've changed. And that's what they've been trying to do, ever since the Abrahamic conversions. We aren't necessarily convinced yet.