This is actually a quite excellent question. Further, it could be extended far beyond simply the hero's journey motif, to encompass many other tropes or structures.

You're certainly correct in that certain real, historical events can be interpreted in the light of more well-known "fictional" accounts - motifs from which are then included in the "historiographical" accounts. I'm not sure how many (Christian) saints actually went into the wilderness (alone), as to mimic Jesus' life...but we could certainly conceive of distant monastic life itself being a type of "wilderness journey"; as well as asceticism in general being a battle against the alluring forces of "Satan." (Fun note: a while back, I made a brief comparison between the hagiography of St. Anthony and some well-known legendary motifs from Buddha's bio, here).

Going back to the Biblical sources themselves: how many data about the life of Paul can really be extracted from the Acts of the Apostles? Many of the life events described therein mirror those in Jesus' life as appears in the gospel of Luke. Did some of these really happen, but then the typological similarities were "played up"? Or, in conjunction with the increasing recognition that events described in Acts are also permeated with motifs from Homeric and other Greek literature (and possibly even modeled on these narratives themselves), does this suggest that we're dealing with a more blatant type of "fiction" here? This has certainly become a more popular scholarly trend as of late.

For another example, take the motif of a besieged city. Of course, in ancient warfare, we can assume that things often unfolded in similar ways: a city may have been surrounded for a long period of time, and so vital resources from outside were not able to get in (leading to motifs of starvation, cannibalism, etc.). In hindsight, a theological justification is sought for these events - the gods are said to have "abandoned" the temples (perhaps due to some sin within the city, or something like that). On the other side, with the conquering party, they may boast that they "totally ravished" and that they killed or enslaved "every last one of them" (even if it wasn't really totally destroyed, or if many escaped death or enslavement). So if we see, for example, quite similar accounts - of, say, the destruction of Jerusalem in the 6th century BCE and its destruction in the 1st century - this may just be due to common tactics or warfare (in addition to the influence of earlier literary accounts / theological ideas on the historiography/mythography of the later destruction).

If we accept the premise, I see several likely consequences:

• post hoc, ergo propter hoc: If we go into a narrative expecting fable-like cohesion, then we may be tempted to see causality in events that are merely sequential.
• role-fitting: The monomyth has set roles for the players in it: threshold guardian, herald, etc. Such roles may unjustifiably limit the interpretations that we have for the involved players. We may cast a person as a villain when they may be more or less than that. Conversely, if we have decided to view another person as the protagonist, we may be inclined to disregard disagreeable parts of their behavior.
• stage-fitting: Likewise, the monomyth has set stages: a call, a set of trials, a triumph, a return. If we view historical narratives through that lens, we risk excluding things that don't fit the formula. For example, the hero is supposed to return changed, a champion of a wider world. This does not always happen.
• an overemphasis on human agency: Personal narratives emphasize persons. This risks the under-emphasis of systems, natural events, institutions, etc. as causes.
• stretching for meaning: Viewing things through a mythic formula encourages a search for the kinds of meaning found in myth. We may force some events to hold greater significance than they really do.

As for OP's final question, I see it at least in part as a methodological concern. We should be worried if we have a bias toward seeing myth-like narratives where there are none.

I'm definitely late to the party, but would have to strongly agree with /u/LieBaron, in that Joseph Campbell's "Hero's journey" - the book which started this idea - is not very helpful to good history.

The question as it stands is predicated on that there is a Hero's Journey, and that the stages of this story are formulated along the lines of Campbell book (called "The Hero With a Thousand Faces"). Alas, while the idea of a single shared story intuitively makes sense, it has some serious, critical flaws. Firstly, it homogenised a lot of different stories that are less similar than they appear - not in the telling, but in the power backing it up - and secondly, Campbell cherry picked the stories that proved closest anyway. Firedrops and I actually talked about that a few days ago on AskSocialScience.

The thing about it is, in plain language, different audiences are going to hear different things. They have different experiences and understandings about the world. Just like someone can watch fireworks and think of celebrations, someone else can watch fireworks and have a serious flashback to 'nam. So if we took this to a cultural level, some things that have great meaning and power in some languages are going to invoke nothing in another. Even if the "narrative" was the same, the structures backing it up - both cultural and personal - are going to ensure it means something different and powerful to different cultural groups and individuals.

By the same token, the same audience is going to hear the same things. We like certain tropes because they have power and invoke meaning in our lives. If you read, for example, Ekalavya (an Indian story), it would mean nothing to a Westerner - and in fact makes most 'normal' Westerners seriously angry, as the "moral" appears to clash with the tropes used. /u/Firedrop also points out Shakespeare in the Bush - (quoting him or her)

[SitB] is about an anthropologist's frustrations trying to explain Hamlet to Tiv elders who keep telling her she has parts of the story wrong (ghosts don't exist, for example) and is interpreting the moral lesson incorrectly. While death, betrayal, madness, and murderous politics may touch on universal human conditions their meanings and interpretations are not necessarily universal .

Who to read; tricky. Theoreticians tend to be about as useful as tits on a snake, when it comes to actually reading them. Have you read Levi-Stuass' "On the Structures of Myth"? Then Derrida's "White Mythology", would probably be awesome.

I am not sure I was of any help whatsoever.

I think the Joseph Campbell's "Hero's journey" is more or less useless when describing any narrative, and for what it's worth you won't see it mentioned (much less used) often in academic literary analysis. The problem, simply put, is that it is at once much too broad and much too narrow - its categories are too broad, and its interpretations too narrow - any narrative will fit into these large categories, but that won't tell us anything about the narratives themselves.

Your question is still valid, though I would use other examples instead. A good example would be the current question on the Ottoman Empire - I think that there is a narrative of 'empires declining' that is not necessarily true, and certainly is only ever true in hindsight, IE after an empire has fallen.

This approaches philosophy or at least science of the mind. It seems to me that the "I" in our heads is a narrative making system. We experience stuff and each of us creates a narrative of our lives. History (the product, not the past) is a narrative we create regarding events. A set of shipping manifests is not history, it is just data. Using that to tell a story about slave transports and sugar and rum is history.

Your question deals with forcing events to a limited set of narratives. That is a potential danger and trap. We have to ignore some detail to make a story and so we can ignore the wrong details.

I think the question has all the facets you mentioned. From a literary perspective, one book comes immediately to mind - Tolstoy was railing about exactly this as far back as the 1860s. War and Peace is about half narrative and half treatise that history is not caused by individuals; that writing history as a narrative starring 'heroes' was false and dangerous. He wrote that history was an accumulation of forces, creating tides that can't really be changed by individuals on a large scale. The book reflects that, painting 'great' leaders (e.g., Napoleon) as victims of history like everyone else, or even more so.

He's pretty hard on the historians of his time, but like /u/American_Graffiti said, it feels like modern historians are usually more aware of this tension.

I actually wrote my senior thesis on this topic in undergrad. I was trying to figure out how much of George Washington's history was historians trying to make his life fit the hero quest to create a sort of history for such a new country versus how much his actual life did fit the hero quest, which naturally helped him fill the role of a hero. Conclusions were bizarrely creepy and unexpected. I'll get my sources for you and be back in a bit. If you want to PM me I can send the paper to you if you're interested in reading it but it is around 40 pages.

If you're interested in exploring forms of organizing information and events besides narratives, I recommend Azuma's "Otaku: Japan's Database Animals."

It's not strictly speaking history (more critical theory, as Azuma's central premise rests on concepts like a grand narrative in a society's superstructure), but its a short read and offers an interesting understanding of how information is organized in a computerized society.

This is a really interesting question, and I feel like I can't give it justice with the time I have at hand right now, but I would like to add to the conversation by pointing out that Hayden White addresses this point in a slightly different way in "The Structure of Historical Narrative". As I interpret White's words somewhat freely, he actually argues that there are 4 'western' tropes (he doesn't necessarily see these as universal) in formal history. Walter Benjamin also has something to say to this kind of topic in "On the Concept of History", where he argues that historical materialism and narratives of the past are in part derived to legitimize certain subjegations (of course, for him this is tied in to the rise of Nazism etc), and that THESE serve as the framework of interpretation. Admittedly, neither Benjamin nor White is specifically speaking to "the Heroes Journey", but they are speaking to metanarratives such as this one.

...the "hero's journey/monomyth." The very structure of narrative seems to sequence around epiphanies and conflict, that though they may not follow the entirety of a monomyth template, they may pluck significant elements from them.

Non-historian here. Can you give an example of how this might happen? What is the hero's monomyth? And how might history look if influenced by some other monomyth? Is the monomyth biologically programmed into us, or is it cultural/learned?

I'm very curious, thank you!