Demythtification

Parallel to External Retcon: taking a legend and revealing what 'really' happened by stripping all the fantastic elements out of it. This sometimes falls flat, because without the gods and magic, the audience might wonder what the point is. If King Arthur is just another warlord with no Lady of the Lake and no Merlin, he had better be made an interesting character in his own right.

Filmmakers sometimes forget this second part. In particular, the onus is on the writer to make the "imagined" historical events at least as interesting as whatever actually inspired the legend (and the actual events sometimes weren't).

If the historical period in which the original story is set is unfamiliar to audiences (and only touched on for versimilitude by the writer for that reason), audiences may assume that the real-life historical milieu so lovingly depicted by the art department couldn't possibly have been the source for the the story they know and love, and is part of the filmmaker's dastardly invention. This is complicated by the fact that Reality Is Unrealistic, not to mention less dramatic, and so, in the course of taking some of the more fantastic elements out, a certain amount of Hollywood History must be added in.

This technique is often used to give an adaptation a grittier and more realistic feel in situations when it is perceived that the fantastic elements in the traditional version might seem too whimsical or even silly to the intended audience.

Expect the hero to become Famed in Story, thereby setting the stage for the rest of the story to become Shrouded in Myth.

The technical term for this technique is Euhemerism, named after a 4th-century BCE Greek, making the trope Older Than Feudalism. Sometimes coupled with a less than subtle Take That against religion, particularly Anvilicious writers will give the characters anachronistically agnostic attitudes towards the gods.

Magical Realism can take the form of Demythtification in a more contemporary setting, or vice versa, especially if your Retroactive Realism involves one or two elements (often the most beloved elements) that are left purposefully ambiguous as to whether or not the supernatural is in play.

When a writer intentionally does this as a way of drawing out what historians "really think" inspired the legends, it is this trope. When a writer makes stuff up by way of Literary Agent Hypothesis in order to rewrite an existing legend, it is an External Retcon, which is a sister trope.

When stripping away the fantastic happens within the same fictional universe that had the fantastic elements in the first place, that's Doing in the Wizard, which is another, related sister trope.

When a writer takes historical accounts and reimagines what actually happened, it is Historical Fiction (or Alternate History if the changes are great enough). When a writer makes a subtle reference to actual history in a work of fiction, it is a Historical In-Joke.

See also Oral Tradition, Twice-Told Tale.

Not to be confused with Defictionalization or Low Fantasy. See Historical Fantasy for the opposite.

Comics

 * In Don Rosa's The Once and Future Duck Gyro, Donald Duck and his nephews go back in time and runs into the (extremly unheroic) warlord Arturius Riothamas (King Arthur) and his bard Myrdin (Merlin). They also accidently create the basis for the legends of the Holy Grail and Excalibur. The main characters manage to thwart Arturius and flee back to the future, but in the end, Myrdin decides to make the entire incident look like a great victory and create a heroic song about "King Arturius and his Narts of the Round Stable", promising that it will be a huge hit in the future. It is based on a genuine theory about the "historic" Arthur.

Film

 * King Arthur (2004) attempts (the key word being: attempts) to present a historically accurate version of the Arthurian legends. No mean feat: the evidence is vague and contradictory. The film takes the Sarmatian Hypothesis and runs with it, stripping out all magical elements in the process. Some elements are right despite seeming wrong: Aluminum Christmas Trees. But most are more the product of the The Eiffel Tower Effect: Hadrian's Wall as the site for the battle of Badon. This bothered critics.
 * Not as much as Picts being present for the Saxon Invasion, though.
 * Or Keira Knightley's leather-bra-and-straps outfit...

Literature

 * N.M. Browne's Warriors of Camlann (sequel to Warriors of Alvana). There are elements of magic, but it tries to address historically plausible explanations for Camelot and Arthur. Though good luck, at points, figuring out who is who with all the alternate naming.
 * The Warlord Chronicles - Nimue, Morgan and Merlin's "magic" is a masterful mix of psychology, timing and chutzpah. The Unreliable Narrator is predisposed to believe in pagan magic, and believes every trick, Merlin and co. pull until Merlin explains in detail how he did it. Sometimes he still believes, despite the explanation. Similarly, pagan ceremonial magic is a mix of psychology, showmanship, trickery, and taking credit for natural occurrences.
 * The waters get muddy in the third book. There are some Contrived Coincidences where genuine magic is also plausible: Ceinwyn's illness just happens to take place at the same time that curses her, and that she briefly gets better while  demonstrates her power to influence her health from afar. And then there's the Grand Finale, where Merlin's magic stone apparently summons magic mist out of thin air.
 * This can be explained by the Unreliable Narrator. Monk!Derfel grows more and more re-attached to his old belief system as the story progresses (which shows subtly in the introduction chapters dealing with the "present"), which can explain how his narrative goes from mostly skeptical in the beginning to more fantastical in the end.
 * Andre Norton's novella "Pendragon: Artos, Son of Marius" - one of the quartet of stories in Dragon Magic - is set in post-Roman Britain. It ends with an explanation of the later legends of Arthur's death - he was secretly buried in such a way as to give his followers hope of his eventual return.
 * Terry Pratchett has a subversion in the story "Once and Future"; of course Merlin isn't really a wizard, he's a time traveller! The stone holding the sword is an electromagnet. (It's also made clear that, even without magic, the Anachronism Stew of Arthurian Britain isn't any history Mervin's familiar with.)
 * Philip Reeve's Here Lies Arthur tells the story of how Merlin (not a wizard) built up the legend of Arthur (not a hero, but a common warlord, and a fairly stupid one at that) using a web of deceit and the help of the book's young protagonist.
 * Mary Stewart's Merlin Trilogy, although Merlin is sorta magical and is teased to be the son of an incubus in the first book. After that, it's made pretty clear who his father is.
 * Sword at Sunset is another stripped-down Arthurian retelling (in fact, one of the first) by Rosemary Sutcliff. This one does contain much more historical plausibility and historical research than the movie King Arthur, though it is left deliberately ambiguous if the "curse" put on Artorius is supernatural or just psychological.
 * Mark Twain's A Connecticut Yankee in King Arthur's Court portrays the magic in the Arthurian legend as fraudsters (including the title character) fooling the ignorant. Also subverted, when said title character falls unconscious for 1500 years so that he can personally deliver the story to Twain.
 * Jack Whyte's Camulod series removed virtually every scrap of magic from the King Arthur tales - except the Made Of Unobtainium Excalibur and a few characters having psychic dreams. Good historical fiction, just don't fool yourself into thinking it's a King Arthur series.
 * Stephen R. Lawhead's Pendragon Cycle series contains virtually no explicit magic, though Merlin is descended from Atlanteans (who are treated like Tolkien's Elves.)
 * Joan Wolf's The Road to Avalon has no magical elements except for Arthur and Morgan (portrayed as Arthur's friend) sharing a telepathic link. Merlin is a Roman-trained engineer.
 * Courtway Jones' In the Shadow of the Oak King similarly strips out the magic except for making Arthur and his half-brother Pelleas telepaths. Merlin is a blacksmith and general wise man.
 * Parke Godwin's Firelord. Followed by Beloved Exile, about Guinevere's later life at the End of an Age.
 * The Sword and the Flame by Catherine Christian (published as The Pendragon in the US).
 * Helen Hollick's Pendragon's Banner trilogy.
 * Black Horses for the King by Anne McCaffrey, told from the viewpoint of a stable boy.
 * The Last Legion by Valerio Massimo Manfredi. Made into a movie with Colin Firth and Ben Kingsley.
 * The Great Captains by Henry Treece. His version of Arthur and co. also appear in The Green Man, a retelling of Hamlet based on the original Danish legend.
 * Excalibur! by Gil Kane and John Jakes.
 * The Lovers by Kate Hawks, about Tristan and Isolde.

Live Action TV

 * Arthur of the Britons
 * In Doctor Who, the Sufficiently Advanced Alien Doctor's apparently Merlin.

Film

 * Arguably, Jesus Christ Superstar and The Last Temptation of Christ, although they don't debate Jesus' divinity, do question him from Judas' point of view, and seemingly do in the wizard with respect to physical miracles and angels incarnate. Rather than being made to look especially fallible, Jesus counsels his followers to be more sensible, but his best intentions are tragically unheeded by his flock.
 * The Man From Earth: while the movie has one supernatural element on which the whole story is based, the way it explains the myth of Jesus is quite realistic.
 * Not supernatural as much as highly speculative. The characters themselves discuss whether it would be scientifically plausible for a man to stop ageing and live indefinitely. They conclude that it's theoretically possible, if highly unlikely.
 * The Messenger: The Story of Joan of Arc. This is a borderline case, however, as more than one interpretation is offered for the Visions, and indeed implied for 'the Conscience'. Of course, since Joan of Arc was definitely a real person, The Messenger might also be accused of going the opposite route and adding fantastic elements (though this gets into a tricky theological debate).

Literature

 * The Jefferson Bible was an attempt by no less a personage than Thomas Jefferson, a Deist who considered Jesus to be a great moral teacher but had a strong dislike for organized religion, to strip the Gospels of their more "fantastic" elements. Deism was a philosophy common in the 18th century that denied the existence of miracles and perceived God as a "cosmic watchmaker" who creates the laws of nature and carries out His will in accordance with them. It still exists but is much less popular and influential than at its peak, and is best recognized today for its influence on Unitarianism.
 * Act of God, similar in style to The Holy Blood & the Holy Grail, raises the hypothesis that the Thera eruption was responsible for the Exodus story. From plagues to Pillar of Smoke By Day, Pillar of Fire by Night, the idea is an interesting one.
 * Shulamith Hareven's The Miracle Hater is a mostly naturalistic retelling of Exodus, a historical depiction of a desert tribe who don't yet have the kind of religion that Judaism would eventually develop into.
 * In Zora Neale Hurston's Moses Man of the Mountain, some of the famous miracles Moses performs in The Bible while leading the Hebrews out of Egypt are really tricks he learned from his first trip into Midian: he crosses the Red Sea because of his knowledge of tides and strikes water from a stone by finding a spring he had once encountered. However, some of his miracles are still as fantastic as the biblical version, and from Moses's perspective there is no difference between them: they're all just applications of his vast knowledge of nature.
 * Gospel of Afranius by the Russian author Kirill Yeskov presents the four canonical Gospels as honest but one-sided eyewitness accounts of "Operation Pisces" by the Roman secret service to undermine right-wing militia support in Judea. While not denying (or supporting) the claim of Jesus' (who is shown as an unwitting (?) victim of the Romans) divine nature, it explains most of his miracles with actions of the Double Reverse Quadruple Agent Judas and his posthumous appearances, with various impostors (one of whom went on to write the Q document).

Video Games

 * Assassin's Creed:

Film

 * Ever After does this for the "Cinderella" fairytale. Among other things, the "fairy godmother" is actually Leonardo da Vinci.

Literature

 * Just Ella by Margaret Peterson Haddix also retells "Cinderella".
 * Confessions of an Ugly Stepsister by Gregory Maguire also does this (excellently) with "Cinderella".
 * The works of Polish fantasy writer Andrzej Sapkowski frequently use this :
 * The novels and short stories of The Witcher series often take obvious Expys of common fairytales and throw everything fairy in them out of the window, often to show a cynical or amusing explanation for the actual plot. It's played with though, since magic and other usual trappings of Geralt's fantasy world still remain, they're more often some sort of Magitek or clever imitations of it than anything else.
 * His more recent "Hussite trilogy" is Historical Fantasy set during the time of the Hussite Wars (1420s). As you'd expect from the subgenre, magic and fantasy elements are quite plentiful, but the bulk of the story is in essence a historical adventure novel.

Theatre

 * Rossini's opera La Cenerentola tells the story of Cinderella minus the magical elements.

Comic Books

 * In Age of Bronze, Eric Shanower's graphic novel series based on the The Iliad, the gods don't appear, and there's no evidence that they actually exist in the world of the adaptation. This is deliberate, as the afterword makes clear. Also, Helen of Troy is only fairly attractive, not beautiful. Odysseus and Agamemnon decide to say she's the most beautiful woman in the world because the Hellene soldiers will fight more willingly than they would for the real reasons for the war, which are more complicated and less glamorous.

Film

 * Troy intentionally strips out the prominent supernatural elements of the original poems -- or renders them ambiguous. The gods are never seen, and never act, despite their large roles as Physical Gods in Homer's telling. Achilles is a Nay Theist who pooh-poohs the gods at every turn. Hector, of all people, paraphrases Stalin: "How many battalions does the sun god command?" The priest of Apollo acts as an inverted Cassandra -- he always gives exactly the wrong advice and is always believed.
 * More ambiguously, Achilles' mother could be a goddess (well, one who really doesn't know the original version would think she is simply a seer rather than a goddess) or a strange but wise woman. Achilles' blasphemy tends to be followed by bad luck, and of course he is shot in both the heel and the chest when he dies, so we still don't know which arrow killed him. There are many other changes from the original plays unrelated to the trope.

Literature

 * David Gemmell's Troy series dispenses with the gods so prominent in the original plays.
 * Dares Phryx (5th or 6th c. CE) and Dictys Cretensis (2nd or 3d c. CE) both wrote more-or-less realistic narratives of the Trojan War, with a strong sense that this is the later-corrupted "real story" (both authors' pseudonyms are names used in Homer -- they're presented as eyewitness accounts by Trojan War veterans); e.g., in Dares, rather than using a giant wooden horse, the Greeks enter Troy through a gate decorated with a picture of a horse.
 * The King Must Die and The Bull From the Sea, Mary Renault's novels about Theseus. Successful in that Renault does make Theseus a complex and compelling character in his own right. She also succeeds in capturing much of the spirit of the myth because her first person narrator, Theseus, believes in the gods and their influence in his life, even if none of the book's events are depicted as blatantly supernatural.
 * Robert Graves
 * Hercules My Shipmate retells the story of Jason and Argonauts. The gods are real for the characters but their physical reality is not clear.
 * Homer's Daughter is based on Samuel Butler's theory that the Odyssey was written by a young woman, who based it on her own realistic experiences, and based the character of Nausicaa on herself.
 * A footnote in House of Leaves, containing an idea that a character in the book thought up and then abandoned, explains the Minotaur as King Minos' deformed son -- the body of a man, the head "of a bull"- who was born so ugly that Minos would publicly accuse his wife of bestiality rather than accept his son as an heir. The labyrinth was a prison so complex, with the Minotaur himself being "gentle and misunderstood," that the Athenians who were "fed" to the Minotaur died mostly of starvation. Guess what the author of that idea (and, hypothetically, King Minos) thinks of Theseus.
 * Ursula K. LeGuin's novel Lavinia is a mostly realistic version of Vergil's "Aeneid," though it does add the supernatural touch of Lavinia having proleptic conversations with the spirit of Vergil.
 * Older Than Feudalism: There is a book called "On Incredible Tales" by one Palaephatus (an ancient Greek author). A nice reading, if you suffer from a really bad case of insomnia.
 * CS Lewis's Till We Have Faces is a retelling of the myth of Cupid and Psyche. The jealousy of Ungit (Venus) for Istra (Psyche)'s beauty is presented as the jealousy of the priest of Ungit for drawing away worshipers. Psyche's "marriage" to the god of the Grey Mountain (Cupid) is being chained to a tree on the side of a mountain as a sacrifice. Orual later finds Istra living on the mountainside, clearly insane and claiming to live in a palace that Orual cannot see..
 * The short story "The Garden of Tantalus" by Brian Stableford, collected in Classical Whodunnits, is a Demythification of the Lamia incident in Philostratus's Life of Apollonius of Tyana, in which the "lamia" is a human, but metaphorically venomous, Femme Fatale, and Apollonius's own "magic" is a combination of natural philosophy and common sense. The story is supposedly written by a student of Apollonius, who is tired of mythological tales attaching themselves to a rationalist philosopher.

Live Action TV

 * Hallmark's miniseries Hercules (2005). The existence of the Gods made rather ambiguous (Hercules being fathered by an escaped prisoner of war with a lightning tattoo), but they do throw in mythical creatures of Ancient Greece. It's heavily arbitrary on when to dismiss the fantastic. In addition, Hercules' Super Strength and fighting prowess is explained as a Charles Atlas Superpower brought on by Training From Hell.

Anime & Manga

 * Osamu Tezuka's Phoenix series often features this, despite the title character being an immortal god-bird. Many characters in the earlier historical chapters are gods and other figures from Japanese Mythology re-imagined as ordinary humans and Strange Beings & Robe of Feathers imply that various mythical creatures are actually aliens or time travelers. Tezuka dispensed with this as time went on, however, with the final completed volume, Sun featuring such oddities as battles between Youkais and Bodhisattvas and retconning the alien angle out of the aforementioned Strange Beings.

Film

 * The 13th Warrior / Eaters of the Dead, which combines the story of Beowulf with Ahmed ibn Fadlan's 10th century travelogue of Europe. In this story, ibn Fadlan joins a Norse rescue mission to face a seemingly supernatural enemy. Instead of Grendel, the enemy is a . Grendel's mother is replaced by the matriarch. The dragon is just an optical illusion created by  as they stream down from their mountain lair. However, the story does dabble in some standard wise woman prophecy and mysticism.
 * The Dark Knight Saga strips the world of Batman of fantasy elements. Batman fights many sci-fi and supernatural characters in the source continuites. In fact, arch-foes like Ras Al Ghul and the Joker are given much less fantastic backstories. The Joker is given less backstory, period.
 * In fact, Ra's is revealed to be not one immortal man but the latest successor in the long line of leaders of the League of Shadows, all calling themselves Ra's al Ghul, and any fantastic abilities are chalked up to a hallucinogenic flower.
 * Although it's basically Historical Fiction, and accurate in many respects (less so in others...), Kingdom of Heaven has tendencies towards this school of film-making with respect to the legends of the Crusades. However, the Director's Cut of the movie heavily implies that the Hospitaller is an angel.

Literature

 * Robert Silverberg's Gilgamesh the King is a retelling of The Epic of Gilgamesh, sans supernatural elements; the "scorpion people", for instance, are just a family with a skin condition.
 * Baudolino by Umberto Eco does this with the "conspiracy" version of the various Grail and Templar legends surrounding the Crusades - the same material that Eco dealt with earlier in Foucault's Pendulum. The historical conspiracy is replaced by two petty criminals and forgers trying to make a profit by selling fake relics. Although it's clearly fiction, and the way that these two characters come up with nearly all the Dan Brown stuff on their own without planning is meant as a joke, the gist of it must be closer to reality than the organised, large-scale conspiracy version.
 * Also, Baudolino himself is basically a medieval Münchhausen.
 * Snorri Sturluson's Prose Edda, one of the major sources for Norse Mythology, uses this technique in the prologue. As a 13th century Christian, Snorri advanced the theory that the Norse gods were warriors who left Troy after it was destroyed, travelling to Northern Europe where their advanced knowledge meant they became chieftains. After they died, hero cults arose around their tombs, which eventually led to them being worshipped as gods. The same outlook is also presented in another work attributed to Snorri, "Ynglinga Saga", the first section of Heimskringla, but here, the Aesir are not identified with surviving Trojans, but an unrelated people whose home city Asgard was located somewhere in southern Russia or the Caucasus, and who migrated northwards to evade Roman imperialism (about a millennium after the destruction of Troy). As Heimskringla is about a decade younger than the Prose Edda, it seems Snorri eventually dismissed the identity of the Norse gods with the Trojans.

Live-Action TV

 * Dexter has pretty much dropped the demonic elements from the books, and made it a (relatively) more conventional series. Well, a conventional series with a serial killer protagonist.
 * He does later refer to his "dark passenger" but only in a figurative sense, not an actual demon.
 * Doctor Who does this occasionally. One of the BBC post-series novels featured the Doctor and Ace wandering into the middle of The Epic of Gilgamesh. Enkidu is a neanderthal, Gilgamesh is a perfectly human Boisterous Bruiser... and Utnapishtim is an alien starship captain, his flood-defying ark is a spacecraft, and the Scorpion Men are robots with lasers. Oh, and Ishtar is being impersonated by an alien criminal who Utnapishtim is trying to hunt down.
 * Almost any supernatural element in the show is explained as either alien or extradimensional.
 * Even vampires turn out to be alien fish using perception filters to appear human. The "teeth" are the product of human subconscious trying to warn the person of a threat.