A form of insanity far more common in fiction than reality, the delusion that one is a famous person, or at the very least the modern reincarnation of same. Napoleon Bonaparte is the most commonly used person for this, possibly because the unusual hat and hand-in-jacket pose are a strong visual that immediately identifies the delusion for the audience. God and Jesus are also frequently seen.
This trope is usually played for comedy, but can also be a bittersweet commentary on contemporary society.
It may also be used to bring extra hilarity to a person already suffering from Identity Amnesia.
Not to be confused with the trope The Napoleon or The Napoleon Complex, where a short person is hostile or violent.
Compare A God Am I. Contrast Thoroughly Mistaken Identity. See also Daydream Believer and Otherkin, for people in real life or otherwise who believe they are reincarnations of mythic/fictional characters (or in the case of otherkin, incarnating the spirits of animals).
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In Astérix and the Big Fight our Roman-era heroes go to see a druid who specializes in treating mental problems. One of the people in the queue is dressed as Napoleon. The receptionist's comment: "No-one knows who this one thinks he is." See also a film example below.
A very early Batman story, "The Scarlet Horde", was about a cabal of scientists led by a man believing himself to be the reincarnation of Napoleon.
An old EC Comics sci-fi story involves an alien invasion scout ship killing a man and stealing his brain, so they can scan it to learn of Earth's defenses. They see men on horses with swords and powder rifles, and cockily decide that their one ship can conquer this primitive planet. They launch an attack...and are immediately shot out of the sky with missiles. Cut to a horrified worker at the insane asylum who just found the brainless corpse of the inmate who thought he was Napoleon.
The Simpsons Halloween comic "Immigration of the Body Snatchers" gives the Springfield Loony Bin an entire Napoleon Ward. It's on the Cliched Patients Wing, right next to the Charlton Heston Messiah Complex.
An Archie Comics story once had asylum employees mistakenly think that Jughead was an escaped mental patient and they brought him back with them. Jughead spends until the entire comic trying to prove his sanity or escape, until he finds out that the cafeteria there serves great food. In the end, Archie comes to try and free his friend, only to find Jughead deliberately pretending he's Napoleon in order to stay for the food. Interestingly, a reprint of the story years later changed it so that he pretends he's Dr. Eggman instead.
Ach!lle Talon has a guy claiming to be admiral Nelson. If you think this belong to Non-Napoleon Examples, check what Nelson is famous for.
Another guy, while never claimng to be Napoleon, wears the green jacket with his hand inside, and owns a Napoleon-memorabilia store.
The 1976 Lucky Luke story l'empereur Smith features a man who declares himself emperor of America. He is rich enough to set up a small private army which he dresses up in French Napoleonic uniforms. Emperor Smith was inspired by Emperor Norton (see Real Life).
De Kiekeboes: Subverted in the album "Een koud kunstje", where the real Napoleon is brought to a mental institution for believing he is Napoleon.
Nero: Both Nero and Meneer Pheip have at one point (Nero in De Draak van Halfzeven, Pheip in De Gouden Kabouter) believed they were Napoleon, dressed up like them and were sent to a mental institution.
In Highlander III: The Sorcerer, Connor is strapped to a bed in the psych ward of a hospital, and uses his first-hand knowledge of the Napoleonic Wars to convince a Napoleon to free him.
In the brief asylum scene of The Shadow movie (in a rather Nightmare Fuel scene showing that the villain after having the psychic part of his brain damaged by a shard of glass and then removed by surgery has been put into a place where his claims of being the mind-manipulating descendant of Genghis Khan will not be believed), the inmates exclaim who they think they are. One of them is a Napoleon. Another, with a distinctly male voice, announces that he is Josephine.
At the end of Batman Forever, the now-institutionalized (and insane) Riddler claims to know Batman's true identity. When pressed, he insists that he's Batman. From somewhere else inside the asylum, we hear another patient respond, "And I'm Napoleon!"
There's a film titled The Emperor's New Clothes in which Ian Holm plays Napoleon himself, and the premise is that he escaped St. Helena and an Identical Stranger took his place. However, once he gets back to France, he is treated as one of these, and ultimately settles into a happy but mundane life.
There's one scene where a doctor (who suspects that Holm's character is Napoleon) takes him to a insane asylum and shows him a courtyard full of men with NapoleonDelusions, so he'll realize the danger of his claims.
In the animated The Twelve Tasks of Asterix, one of the people who just left "the place that sends you mad" is wearing a paper hat and has his hand in his shirt. Given it's made by Franco-Belgians, more than acceptable.
In The Exorcist, Fr. Karras tells Mrs. MacNeill that Pazuzu/Regan claiming to be the Devil "is like saying she's Napoleon."
A visitor in a mental hospital is given the chance to speak to two mental patients. After a long, interesting conversation in which both patients come across as particularly articulate and well-adjusted:
Visitor: So, sir, I’m quite curious: why are you hospitalised here?
Patient 1: They refuse to believe I’m Napoleon Bonaparte.
Visitor: I see... And how do you know you are Napoleon Bonaparte?
Fredric Brown's "Come And Go Mad", a rather complicated sci-fi novella from 1949, involved a man who had once been institutionalized for believing he was Napoleon. He returned to the asylum to uncover a conspiracy, and discovered that he was, in fact, Napoleon—body-swapped through time by a conspiracy of red and black ants who secretly control all of human history. (Not to be confused with the historical novel The Red and the Black.) The revelation drives him to violent insanity; he undergoes electroshock therapy and returns home "cured", believing himself to be a salesman.
Invoked in Poul Anderson and Gordon R. Dickson's Hoka stories. While the wildly imaginative Hokas love playing sustained imaginative games and taking on roles, so that a Hoka can be Sherlock Holmes, Queen Victoria, the Lone Ranger, the Duke of Wellington, etc. — only when speaking of a Hoka who is Napoleon does Alex feel the necessity to explain that a Hoka can be perfectly sane and still call himself Napoleon. (Well, by Hoka standards.)
Mentioned (but probably doesn't happen) in Animorphs, where Tobias wonders to himself if he's not in an asylum full of people who think they're Washington, Napoleon, or red-tailed hawks.
In the Horatio Hornblower short story The Last Encounter, a stranger calls on the retired main character (a veteran of the Napoleonic wars) claiming to be Napoleon and begging the loan of a carriage so he could return to France in time to run in the upcoming Presidential election and reclaim his rightful position. The stranger turns out to be Napoleon III.
In I Never Promised You A Rose Garden, Deborah's parents have put off explaining Deborah's mental illness to her sister Suzy. They fear she will be traumatized, but she already suspected something and her only question is "It's not like she's Napoleon or something... is it?"
Live Action TV
A Night Court episode has Harry end up in a holding cell for the mentally ill. 'I'm in here, with the Napoleons.' Bonus points: all of them growl when Waterloo is mentioned.
A The Two Ronnies sketch featured the two as men in an asylum, both apparently suffering from this delusion. More of an Invoked Trope, however, as neither is actually mad - they are instead pretending to be in order to avoid the requirement for a job.
The Prisoner episode "The Girl Who Was Death" was an oddly loopy adventure set outside the Village, where No.6 is out to stop a mad scientist who fancies himself Napoleon (complete with a Josephine) who is plotting to blow up London. It all turns out to be a bedtime story No.6 is telling a nursery full of children, where he'd cast No.2 as Napoleon.
Jokingly invoked in a Mash episode in which Hawkeye deals with nightmares and sleepwalking, during which he imagines he's a little kid back home in Maine. The Tag to the episode has Klinger congratulating Hawkeye on what he assumes is a new form if Obfuscating Insanity to get discharged from the Army.
Klinger: It is an act, isn't it? Hawkeye (tucking his hand in his shirt and affecting a French accent): Mais oui, Josephine, I'm as sane as you.
"They're coming to take me away, ha haa!" is a song from The Sixties about a man who will be soon taken to the asylum. Its author is Napoleon XIV. The guy's sane, only playing the image of Napoleon-wannabe loonie.
Flanders and Swann had a song, "The Elephant", in which an elephant claimed to be suffering from this. It makes marginally more sense in context.
I suffer from Schizophrenia. It comes on me in spells. Sometimes I'm King of Armenia, and others I'm Orson Welles. I tell them I'm Napoleon, and all that sort of bunk. They never guess that all the time I'm laughing up me trunk!
In Bleak Expectations, this is somewhat justified, as England has just emerged from the Napoleonic Wars. And therefore all patients on the insanity ward think they're either Napoleon or The Duke of Wellington, and fights are daily occurrence.
David Mitchell: Crazy people don't do that sort of thing as much as you'd think. There's a lot more unhappiness and self-harm, and a lot less thinking you're Napoleon.
One Gahan Wilson cartoon has a psychiatrist's patient, dressed as Napoleon, sitting up on the couch and reading a dispatch while an officer in a Napoleonic uniform stands at attention. The psychiatrist fumes, "We'll never get anywhere with these constant interruptions from the front!"
Parodied by the Cheapass Games release Escape From Elba, in which you play Napoleon. So does everyone else. And each Napoleon is trying to escape the island of Elba (or at least be at peace with the fact that they're obviously crazy and trapped with a bunch of other Napoleons).
In the Book of Madness from the old WOD's Mage: The Ascension, the book explained how Marauder Madness levels worked using the Napoleon Delusion - believing you're Napoleon in the court was a higher level than believing you were Napoleon on campaign, than believing you were Napoleon time displaced or reincarnated, and the lowest level was believing someone else was Napoleon.
An NPC in Gamma World is a sentient bear that thinks he's Napoleon Bonaparte. Given that he has an army of sentient animals at his command, who's going to argue?
In the game Psychonauts, one character in an asylum claims to be Napoleon. In fact, he's a direct descendant of Napoleon fighting off a Genetic Memory of his ancestor. Unlike his diminutive ancestor, Fred Bonaparte is tall and has no particular love of victory although losing repeatedly to inmate Crispin Whytehead at a board game conveniently named "Waterloo" was enough to drive him over the edge and cause the aforementioned Genetic Memory to take over. He wasn't even a patient initially, he was the head orderly until his slide into semi-madness. Raz then enters Fred's mind and helps him win a game of Waterloo against Napoleon. Seeing his descendant win and regain his confidence pleases Napoleon and decides to leave him alone.
There was a BBS door game way back in the days of the Internet called Sanitarium in which the weapons salesman was Napoleon. Or at least he said he was - given the name of the game, you can obviously guess where it took place, and the state of its inhabitants.
At the end of his best-known cartoon, he finally confronts the dog about why he has been chasing him "all through the picture." The dog answers that it's 'cause he thinks he's Napoleon.
Dog: Butcha ain't. * puts on hat* I am!
Futurama: In "Insane in the Mainframe", Bender briefly acted like he was under a Napoleon Delusion, though a skewed one, at the robot asylum. At another point in the episode, Bender is listing some of the great things about living at the asylum. One of these is "two Lincolns for every Napoleon."
"Let me tell you all a story 'bout a battle called Waterloo!"
The origin of this trope is believed to have occurred when John D. Rockefeller had donated money to help restore the Eastern State Mental Hospital in Williamsburg, Virginia. While there, he was walking the grounds and introduced himself to a patient. The patient did not actually believe he met Rockefeller and he sarcastically quipped that he was Napoleon Bonaparte.
Semi Truth in Television - after going crazy from syphilis, the French playwright Georges Feydeau thought that he was Napoleon III.
Francisco Solano Lopez, dictator of Paraguay (1826-70). In one of the tragicomic episodes that occasionally punctuate South American history, he started a war with three countries at once, leading to his death, along with most of his subjects, the partial dismemberment of his country and its economic devastation for many decades thereafter. So yeah. Don't Try This at Home.
Also, Simon Bolivar, one of the great Liberators of South America, modeled himself after Napoleon, but he wasn't insane and actually met with some success.
Antonio López de Santa Anna, the man that controlled Mexico's political scene for the first half of the 19th century, nicknamed himself "The Napoleon of the West". He is remembered today for losing half of the country and subsuming the rest in political instability and civil wars.
Charlie Caligula deliberately based his criminal "empire" and theme on both of the above, making him a borderline example; he doesn't actually think he's Caligula, but likes to pretend.
In "The Goofy Superman!" first printed in Superman #163, Clark Kent, behaving erratically due to Red Kryptonite, is admitted to an insane asylum, where they believe him to be a lunatic who thinks he's Superman. There are several actual delusional patients, including a Napoleon. The most important is a "General Grant," who quickly realizes that Clark is the genuine Superman. (He's crazy, not stupid.)
In a multipart story more recently, Brainiac downloaded his own mind into Superman's body ... and Superman's mind into a young boy in a Bedlam House who believed he was Superman. In the end, Superman mindlinked with the boy, found out the reason he wanted to be Superman so badly, and they took on Brainiac together.
At the Cereal Convention from The Sandman, at least two of the serial-killer attendees considered themselves to be God. Their name tags designated them "God 1" and "God 2", presumably based on who'd gotten to the registration booth first.
Even better, a ranting lunatic claims that "God" speaks to him. One of the "God"s attending responds with something along the lines of "No I don't, I don't even know you."
A Golden AgeBatman story has a non-insane Joker (this'll tell you how old the story is) get himself committed to an insane asylum in order to pump an inmate for the location of a McGuffin. In order to find out what he's up to, Batman has himself committed in the disguise of a stereotypical mind-reading Eastern mystic (turban and all). The inmates include the mandatory Napoleon, an Issac Newton and... a Batman, complete with full costume. Hilarity ensues when the Joker captures the real Batman after seeing through the fake mystic guise, only for the fake Batman to turn up to rescue him — and then decide that Bruce (who has doffed his disguise in an attempt to confuse the Joker) must be the Joker! With the real Joker standing there watching, of course. In the end, the Joker is so confused that he has to explain that he's not really mad and it was all a plot, simply to convince himself that he's actually sane! Boy, they couldn't do that one these days...
An issue of the M.A.S.K. comic book is centered around an escaped asylum patient who thinks he's Guy Fawkes. There is also a patient who thinks he's Napoleon, but he's not important to the plot.
In the movie Bubba Ho Tep, it's left to the viewer whether or not the main character and his friend are really Elvis and JFK, or just really, really delusional. Oh, and the guy who thinks he's Kennedy is played by Ossie Davis, a black man.
The Ruling Class features Peter O'Toole as an heir to a noble title who believes he's Jesus. He's put into psychiatric treatment, and ends up believing he's Jack the Ripper.
In the sequel, air traffic controller Steve McCroskey (Lloyd Bridges) is said to have gone senile, and now "thinks he's Lloyd Bridges."
The film and play They Might Be Giants (not to be confused with the band named after it) is about a wealthy man who has come to believe that he's Sherlock Holmes. His psychiatrist is fittingly named Dr. Watson.
In Revenge of The Pink Panther, Clouseau, dressed in women's clothing, is dragged by the police to a psychiatric hospital. He insists that he isn't crazy, that he's Europe's greatest detective, and gets confronted by a patient who maintains that he is Europe's greatest detective - Hercule Poirot.
In The Dream Team, one of the main characters believes himself to be the second coming of Jesus.
In K-PAX, one inmate in the asylum is a woman who thinks she's the Queen of England.
The Swedish film I rök och dans has an accountant going mad from stress and believing he is King Charles XII of Sweden. He then proceeds to the Nordic Museum to grab "his" clothes and armor.
In The Cannonball Run, Roger Moore plays Seymour Goldfarb, Jr., who is suffering from the delusion that he is Roger Moore.
This old joke:
Psychiatrist: Congratulations! You're cured!
Patient: Cured? I used to be Julius Caesar! Now I'm nobody!
As detailed in Making Money, the Discworld equivalent is Vetinari Delusion. The main villain is shown descending from wanting to be like Vetinari and having Vetinari's posessions stolen to better emulate him, to actually believing he is Vetinari. At the end of the book, he's shown to be put into the "Lord Vetinari Ward" in the local nuthouse, along with a bunch of others.
Referenced in The ABC Murders by Agatha Christie; Hercule Poirot, explaining that a madman's actions always make sense if you understand his peculiarly biased point of view, uses the example of a man who believes himself to be Mahatma Gandhi.
Kathryn Hulme's The Nun's Story:
Averted in the case of the Abbess, who Sister Luke thinks must be delusional (but isn't).
A Larry Niven short story concerns an epidemic of people becoming convinced that they're Superman.
There's a Norman Spinrad short story ("It's a Bird! It's a Plane!") also involving an epidemic of people who believe they're Superman.
Dr. Felix Funck: He think's he's Superman, and he's so crazy that he is Superman! This is a job for SUPERSHRINK! ... Wait for me, Superman, you pathetic neurotic, you, wait for me!
In The Ball and the Cross by G. K. Chesterton, the two protagonists realise they've broken into a lunatic asylum when the two men they've met claim to be God and the King. Since the protagonists are, respectively, an atheist and a Jacobite, they each take the opportunity to vent some steam at their respective hate figures.
House of Leaves features a throwaway anecdote from Johnny Truant about a former landlord who woke up believing he was Charles de Gaulle.
Referenced, during a discussion of religion, in The Last of the Venitars.
The Beast: I once visited a mental institution where four hundred patients claimed to be God. I suppose it is unlikely they were all lying.
In the Honor Harrington novels, the Andermani Empire was founded by Gustav Anderman, a mercenary who believed that he was the reincarnation of Frederick The Great, and modeled the Empire after historical Prussia. Unlike most examples on the list, Anderman was not only insane, but also highly competent. He passed on both traits to his successors and at the time of the story the Andermani Empire is a vibrant and prosperous, though authoritarian, militaristic and ever-so-slightly invasion-happy, interstellar empire.
Live Action TV
In the Babylon 5 episode A Late Delivery from Avalon, we meet a passenger that is convinced that he is the reincarnation of King Arthur, returning in Earth's, and therefor Britain's, darkest hour. It turns out that he is in fact the person who fired the starting shot in the Earth-Minbari War and has suffered a serious case of Survivors Guilt. He is healed when "The Lady of the Lake", or Delenn, retrieves his Excalibur, symbolising that she, and the Minbari Race forgives him.. It should be noted that this is not played for humor. The characters — having met another historical characterpreserved by the Vorlons — seriously consider the possibility that he is King Arthur.
Somewhat amusingly, after being "healed", he keeps up the personality, and goes to help the Narn resistance.
A teenage boy on Boston Public also became convinced he was Jesus after he saw a little boy run over by a bus and later received a nasty electrical shock from a projector. He managed to convince a few other people too.
In another episode Harvey believes he is George Washington reincarnated. The interesting bit is that he is so knowledgeable about Washington that he actually convinces his class that there is at least a chance that he might really be the founding father reborn.
In the Community episode "Studies In Modern Movement", Britta picks up a hitchhiker to prove to Shirley that she has a moral compass despite being an atheist. This backfires on Britta when the hitchhiker reveals that he is a devout Christian. Shirley is thrilled, but then it backfires on her when the hitchhiker turns out to be wacko who believes that he is literally Jesus Christ (oh, and "Jesus" thinks marijuana should be legal). Finally, he declares that he's going to sing a song he wrote about race-mixing called "Don't You Do It", prompting Britta to slam the brakes and both Britta and Shirley to yell "GET OUT!"
Lois and Clark had a woman who thought she was Mary Todd Lincoln. She ends up witnessing Clark using his powers, but then she starts calling him General Grant.
A Mash episode had a soldier convinced he was Jesus. Unlike most examples, there were some who speculated that he was faking it to go home. Turns out he wasn't. The Tag showed Klinger declaring that he was Moses, complete with costume, in an effort to repeat the soldier's success at getting sent home.
Also, in the finale episode when Hawkeye is placed in a mental hospital, he mentions to Sidney that there are two patients suffering from this, one of whom thinks he's General MacArthur and "wades ashore in his bathtub every morning".
Barney Miller had an arrestee who believed he was Jesus, as well. Since he had previously thought himself possessed by Satan, this delusion was kind of therapeutic.
Seinfeld featured a woman who was worried George might be mentally unwell. George almost convinced her otherwise, until she saw him in the street dressed as Henry VIII.
The Hercules: The Legendary Journeys episode "Reign of Terror" had King Augeus believing he was Zeus, even calling Hercules and Aphrodite his children. Hera grants him powers roughly equal to the real Zeus and orders him to kill Hercules. He obeys, wanting to please his "wife" and angry that his "son" had disrespected him earlier. After he is defeated and the power leaves him, he seemingly goes back to normal, but then starts calling himself Ulysses.
Mystery Science Theater 3000: characters would regularly suffer a mental breakdown and become convinced that they were someone else - most famously Mike becoming convinced that he was a) Carol Channing and b) Captain Janeway, but Crow spontaneously becoming a character from the movie they were watching was far from unheard of.
Met a man on a street last night, said his name was Jesus Met a man on a street last night Thought he was crazy 'til I watched heal a blind man I watched him heal a blind man, now I see.
The song "Committed to Parkview" as sung by the Highwaymen, mentions a fellow who thinks he's Hank Williams (does not specify Junior or Senior) and his singing.
The Dire Straits song "Industrial Disease" includes the line "Two men say they're Jesus. One of them must be wrong..."
French rapper Kamini's song "Psychostar Show" is set in an asylum. One of the inmates thinks he is a tsar (he is named Edouard, to create a rhyme).
There's Edouard, who thinks he is a tsar
In Warhammer 40,000, members of the Blood Angels Space Marines chapter would sometimes permanently succumb into so called Black Rage, in which they believe they're the Chapter founder Sanguinius. The rest of the chapter rounds them up into Death Seeker squads when possible, or else just locks them away. It's normally played for drama... but you can't really help but throw in a few jokes about it.
They have a reason; the death of their angelic Primarch left a psychic imprint across the entire Chapter, permanently cursing them with that insanity, and a thirst for blood...
In the Shadowrun game-universe, professional baseball players use skillsofts that perfectly mimic the performance of historic ball players, allowing for proxy match-ups between such combinations as Ted Williams vs. Mark McGuire, or two different seasons' Babe Ruths playing against one another. In the short story that introduced this idea, an ex-player who'd been chipping Babe Ruth when he was struck on the head by a line drive suffered brain damage as a result, causing the Babe's personality to be imprinted permanently over his own.
Arthur Kopit's play Chamber Music is about a group of women in an insane asylum who think they're various historical figures, including Susan B. Anthony, Gertrude Stein, Joan of Arc, Amelia Earhart, and Mozart's wife.
There was a cabaret sketch with two guys speaking in Gratuitous French, only to be interrupted by a doctor:
Doctor: Well, here did my Froggies hide, in the boiler room! Get back to the ward, guys!
The Physicist has 3 characters, an Isaac Newton, an Einstein, and one who believes he is simply visited by Solomon. Einstein is only pretending for the benefit of Newton, because he believes that he is actually Newton.
The titular Elisabeth visits patients in an insane asylum while trying to distract herself from her unhappy life as Empress of Austria-Hungary and meets a patient there who believes herself to be Elisabeth. In a twist on the trope, the real Elisabeth envies the woman's ability to be happy in this delusion when she herself is so miserable. She has to consciously tell herself to stay strong and not give into the temptation to allow herself to go mad too, where they can "only bind your arms but leave your soul free".
In Arsenic and Old Lace, one of the Brewsters believes he's Teddy Roosevelt. He continually relives the battle of San Juan Hill by charging up the stairs, and makes excavations in the basement to dig locks for the Panama Canal and bury alleged yellow fever victims. His aunts note that this is largely voluntary on his part; at some point in the past, when they suggested he be George Washington for a change, he sank into a week-long funk "and just wouldn't be anybody." When he has to be intimidated, the best way to do it is to claim you're Woodrow Wilson. In the movie version, the asylum director complains that Happy Dale already has a surfeit of Teddy Roosevelts, and sadly, no Napoleons.
Unit 2013: Well, he's supposed to. Problem is he's got multiple personalities — all of them Lincoln.
Robotic Lincoln: I was born in two hundred log cabins.
The Batman comics and animated series also had Maxie Zeus, who was under the impression he was the Greek god—though sometimes the delusion seemed to be more playing a part than genuine insanity.
An episode of The Simpsons had Duff Man working in a men's shelter after being fired from his mascot position. After the family convince him to come out of his 10-Minute Retirement and he rips off his suit to reveal his old costume a scraggly looking man is seen saying "Then if he's Duff Man... I must be Jesus!" and promptly jump out a window.
There's also the episode Stark Raving Mad where the family befriends a large, bald, white man... who insists he's Michael Jackson. The joke of this episode is that Homer apparently has no idea who Michael Jackson is, even when the patient names several things that made Jackson famous it doesn't ring a bell with him. Thus, understandably, he just accepts that this huge white man is probably who he claims to be. (Though they did get the real life Michael to voice the impostor).
One episode of Captain Planet had Gaia losing her powers and becoming homeless. Of course, no one believes her when she tries to explain that she's The Spirit of the Earth. Among the homeless are two men who think they're The Red Baron, and one guy who thinks he's William Shakespeare.
Avatar of Supermegatopia, a former archaeologist with multiple personalities, repeatedly assumes the identity of various deities, such as Quezalcouatl, Thor, Set and Jehova. (She also uses the ancient UFO she found to simulate divine powers.) Unfortunately she must not have been an attentive student, since she gets a lot of details wrong, such as referring to Thor's hammer as "Mitch". (Not to mention several of her divine identities are supposed to be male, and Avatar is very much a woman.)
Subverted in thisGirl Genius comic. Agatha thinks Tarvek has this sort of delusion because he claims to be the Storm King. He explains that he just means that he is the current holder of that inherited title.
A surprising number of people suddenly declare themselves as a prophet, messiah, or Jesus returned on entering Jerusalem.
Hong Xiuquan, the founder of the "Heavenly Kingdom of Transcendent Peace" and leader of the Taiping Rebellion (1850-1864) in China, proclaimed that he was the younger brother of Jesus. The rebellion cost 20-30 million lives, making it distinctly Dude, Not Funny!.
During the French Revolution, one of the seven prisoners in the Bastille at the time of the storming was supposedly an old man who thought he was Julius Caesar. This is, of course, before Napoleon was famous.
The Three Christs of Ypsilanti documents the unusual case of three men who claimed to be Jesus Christ met in a lunatic asylum. The psychiatrists capitalized on this to try to devise a treatment, alas to no avail.
George Patton claimed that he lived previous lives so that he could fight in every (major) war in history.
Emperor Joshua Norton of San Francisco was well known in the latter part of the 19th century, proclaiming himself as the emperor of the US and protector of Mexico. He would be often seen inspecting public transportation for defects as a form of quality control. The citizens liked him so much that they went along with this to the point that his homemade currency was accepted in fine restaurants all over the city. City officials even made him a new and improved outfit. However, it was found at the time of his death that he hadn't a penny to his name.
Downplayed in that he did not he did not believe himself to be anything other than Joshua Norton, whether by reincarnation or not. It is just that he also believed that Joshua Norton had been made Emperor.
Internet crackpot Archimedes Plutonium claims to be the reincarnation of Archimedes.