King Incognito

"You mean, the guy who collapsed on the side of the road and mooched food off of us was the son of the emperor?"

- Edward Elric, Fullmetal Alchemist

A special case of Chekhov's Gunman. The heroes and/or villains run into a seemingly unimportant person, usually a beggar or common criminal. Later we discover this person is actually someone of great fame and importance (a king/powerful wizard, etc), and that he/she had disguised him/herself to walk among the general populace unnoticed.

This may be a Rags to Royalty situation, if the king must stay hidden for his own safety. However, it is never a case of a Secret Legacy; the king always knows that he is the king, and is generally plotting for when the Rightful King Returns, or has been using a Decoy Leader to rule. If the central character is the King Incognito, then this is I Am Who?.

Frequently serves as a Deus Ex Machina, or can lead to a Right in Front of Me moment. Kneel Before Frodo often results. God Was My Co-Pilot and Angel Unaware are the supernatural versions of this trope.

If this character isn't that good at passing for common, he may be Rich in Dollars, Poor In Sense.

Compare Modest Royalty, Secretly Wealthy. Contrast with Ermine Cape Effect and Mock Millionaire. Sub-Trope of Secret Identity.

Anime & Manga

 * In Yu-Gi-Oh GX, Chazz runs into a scruffy-looking guy outside North Academy who tells him about the requirements to get in. When he finally does get in and beats every student in the school, the scruffy guy reappears and reveals that he's actually the one who runs the academy.
 * In season 2, Jaden beats Aster Phoenix, supposedly the best duelist in the world. He doesn't learn Aster's name until Syrus tells him.
 * Mai-Otome plays a double case of this with Mashiro and Takumi both sneaking out be among the general population and unknowingly meeting up with each other while their bodyguards try to keep up the Masquerade.
 * The prequel Sifr features a male example.
 * Crusnik #3/The Methusela Empress/Seth in Trinity Blood; She poses as a human tea vendor around her city using an Amidala/Padme decoy system (though the decoy looks much older).
 * The Principal in Great Teacher Onizuka learns of Onizuka's true nature this way.
 * In The Twelve Kingdoms, Shoryuu the Emperor of En does this a lot. He claims that listening to gossip in brothels is a good way to find out what's really going on. It seems to work.
 * Also, the recently crowned Yoko goes on a sabbatical like this early on to familiarize herself with her empire. She ends up joining a revolt against her own government (which had become choked with corruption before her ascension).
 * Hotohori in Fushigi Yugi is always doing this. And has, on occasion, intentionally combined it with Dude Looks Like a Lady.
 * Used absurdly straight in Moetan, where the Badass Longcoat Dandy is revealed to be the King of the vaguely defined Magical Kingdom all along. Ridiculously Shounen battles ensue.
 * In Rose of Versailles, Queen Marie Antoinette tries to go to a party incognito (just not revealing she's the queen, since she's still clearly a noble in a Pimped-Out Dress), but her bodyguard Oscar just has to challenge the guy chatting her up. And so began another one of the series's sources of drama.
 * Lelouch, of Code Geass. Slight subversion in that he's only a prince, and not even close to being the crown prince. (He's 17th in line for the throne, at least he is at the beginning of the series.)
 * It runs in the family. At the series' beginning, he lives with his sister, a princess. As well, Euphie meets Suzaku whilst pretending to be a commoner so she can see the settlement.
 * Happens frequently in The Five Star Stories. It's a favorite activity of Emperor Amaterasu, but then, disguising yourself is the easiest thing in the world to do when you're a literal divine emperor.
 * Shi Ryuuki from Saiunkoku Monogatari does this a lot. Not that he always succeeds; Shuurei saw through his disguise immediately when they first met (he was using the name of someone she had met not ten minutes ago, among other things). He does manage to pull it off at other times, though - at least once so well that when he reveals his identity, his subjects don't initially believe him.
 * Ling Yao and Mei Chan in Fullmetal Alchemist, although in Mei's case, being the emperor's daughter doesn't really get her all that much. Ling on the other hand is such a dork that when the other characters find out who he is, they almost injure themselves laughing.
 * Actually, they're picturing him in pantaloons with a white horse and a shiny crown. The Eastern concept 'son of the emperor' and the Western concept 'prince,' especially as percieved by Easterners, are not precisely analogous, so...
 * Also, Obfuscating Stupidity, even if the falling-over-and-demanding-food thing was later Ling's Something Only They Would Say in a plot-relevant way.
 * Usagi, Mamoru and Chibiusa of Sailor Moon. Though to be fair, the former two were only a royalty in their past lives and of Kingdoms that have been defunct for an unknown amount of time and weren't aware of this until after the series starts. The latter is a Kid From the Future where Usagi and Mamoru have become Queen and King of the earth and is known to be a princess in her time.
 * The fifth episode of the second season of Strike Witches is essentially an extended Shout-Out to Roman Holiday.
 * In the The Legend of Zelda for The Legend of Zelda Ocarina of Time, Link, during his trip to Hyrule Castle Town, meets a little girl and plays with her all day (including going on a semi-disasterous Bombchu Bowling excursion). She's actually Princess Zelda, of course, temporarily run away from the castle to have some fun.
 * In The Heroic Legend of Arslan Anime, Arislan is hoping to get some information out of some prisoners his forces recently captured, so he disguises himself as a servant and arranges things so that he gets assigned to deliver food to each of the prisoners he's most interested in. Estelle/Etoile confides in the "servant" that she has heard that Arislan is a Complete Monster. He responds by feeling the top of his head. When she asks him why, he replies that he's checking to see if he has horns, giving away his identity.
 * Queen Dianna in Turn a Gundam is incognito amongst the Earthrace for most of the story, due to a practical joke she played getting more than a bit out of hand (she switched places with an Identical Stranger and they were separated before she has a chance to switch back). The leaders of the Earthrace do become aware of her situation, as does her personal bodyguard back with the Moonrace, but the general public on both sides has no idea.

Comic Books

 * In the World of Warcraft comic, Lo'Gosh, an amnesiac human with uncanny fighting skills who was forced into being an Orc gladiator, turns out to be.
 * In one issue of The Sandman, Augustus Caesar disguises himself as a beggar to make plans that will not be overheard by the gods.
 * For a few issues Tony Stark decided he didn't want to be Iron Man any more so he gave away his fortune and went to Silicon Valley under the alias of Hogan Potts. He worked as a normal grunt at a company.

Film

 * Queen Amidala of Star Wars frequently disguises herself as one of her own handmaidens. (OK, in this case it's just so that the assassins will shoot the wrong woman, which proves to be entirely justified.)
 * In Kurosawa's The Hidden Fortress (which later went on to influence Star Wars), a princess and a general of a defeated kingdom disguise themselves as peasants in an attempt to smuggle themselves and their kingdom's treasury to safety.
 * One of the princess's servents also dies in her place earlier in the movie (off camera). Look familiar?
 * Prince Edward in A Knight's Tale, who pretends to be a knight of no great repute in order to compete in tournaments.
 * Played with in that his disguise fools no one, and his opponent backs out of the tournament rather than risk the king's wrath. William, on the other hand, has no compunctions about challenging him.
 * The disguise worked fine, as William faced "Sir Thomas Colville" in the previous tournament without realizing who it was. Even Adhemair, who was running commentary for Jocelyn during that joust, had no idea who Colville was the first time around. It just didn't stay a secret in the next tournament.
 * In Dogma, God herself takes a human form in order to visit the Jersey Shore and play skeeball.
 * The twist at the end of the Sherlock Holmes movie Pursuit To Algiers is that Holmes has disguised the about-to-be-crowned-king prince as a ship's deckhand and a cop as the prince to throw the prince's enemies off the trail. He doesn't tell Watson because he fears that Watson would give it away by treating the "deckhand" with the sort of respect he would normally show royalty.
 * Subverted in Alexander Korda's The Thief of Bagdad, in which the vizier convinces the king to walk among his people dressed as a commoner--and then takes over the kingdom in his absence.
 * He's gone for a day. Easiest. Usurpation. Ever.
 * In From Hell, is Prince Albert Victor Edward, the grandson of Queen Victoria.
 * In Roman Holiday, Audrey Hepburn plays a princess who escapes her bodyguards and handlers to have fun touring Rome with a journalist played by Gregory Peck.
 * A Kid in King Arthurs Court had King Arthur posing as a peasant to save his daughter.
 * Becomes a major part of the plot of The Adventures of Robin Hood.
 * Prince Akeem in Coming to America. Unsatisfied with how passive his bride-to-be is, Akeem and his friend Semmi travel to New York, where they pose as working-class African college students, so that he can find a woman who will love him for who he is, rather than what he is.

Fan Works

 * In the My Little Pony: Friendship is Magic fanfic "Sunny Skies All Day Long", Princess Celestia tires of everypony constantly kowtowing to her out of fear and respect. At her sister Luna's suggestion, Celestia spends a day in Ponyville disguised as an ordinary pegasus named Sunny Skies.

Folklore

 * In the older versions -- pre-twentieth century -- of Robin Hood, the king (who may be Richard the Lion Hearted or, if the ballad is old enough, a King Edward) disguises himself to get Robin Hood to capture him. Due to Robin's role in the Rightful King Returns in twentieth century works, this has become less common, but not unknown.
 * King Matthias the Just (aka Matthias Corvinus) of Hungary has hundreds of tales depicting him as this, using it to expose corrupt lords or to learn about the problems of his people. (I haven't seen a lot of English translations, unfortunately.)
 * Popular tales about Polish king Casimir III the Great ascribe him the habit of wandering in beggar's disguise and asking for food. After such a visit he always re-visited said people with his whole court and revealing the results of previous test to public. The most popular version involve king visiting mean noble who mocked his poverty and poor peasant who shared his last loaf of bread with stranger and asking him to come to baptism of his child. Nest Sunday king's carriage stopped by knight's castle just to warn him about underestimating people and king with whole court come to peasant cottage when they threw a party to celebrate peasant's son's baptism. The king was a godfather, promised to take care of whole family and gave loaf of bread in exange for that he had eaten before. It was made of pure gold.
 * In the old fairytale "King Grizzly-Beard," the eponymous king goes through several disguises to get (and to get back at) the princess.
 * In Chinese folklore, famous government officials (especially ones well known for a strong sense of justice) were said to disguise themselves in plainclothes to better spy understand the people he was ruling over.
 * This is also a very common thread in Arabian or Islamic folktales, too.
 * The Jewish folktale "The Sword Of Wood" has a king visit a cobbler without him knowing who he is.
 * This was probably where the King of Jordan got the inspiration to do it in Real Life (and more than once).
 * Toyama Kagemoto is celebrated in both folklore and Jidai Geki for Wandering The Earth (well, Japan at least) in disguise and righting wrongs after he reveals his true identity in dramatic fashion.

Literature

 * Used by Thomas, Lord of the obscure British castle of Magnus in Sigmund Brouwer's Wings of Dawn; officially, he's terribly sick and close to death for the last six months, while in reality he's been in hiding from the Druid conspiracy that seeks his castle and his books, and terribly sick of being stuck inside that long, so he goes undercover to get some fresh air and find out what's happened in the meantime. Good thing, too, since the Druids strike while he's gone.
 * Happened at least once in The 1001 Nights: In "Two Sisters Who Were Jealous of Their Younger Sister", the Sultan, having just buried his father and assumed the title, disguises himself to check out how his people are receiving the change. He overhears three sisters discussing their "If I could have one wish" fantasies, in which one says she'd marry the Sultan's chief baker, the next says she'd marry the chief cook, and the youngest says "Nothing less than the Sultan himself" - so the Sultan decides to make their wishes come true.
 * According to these stories, caliph Harun al-Rashid also liked to do this.
 * He wasn't necessarily good at it, though, nearly getting himself killed in The Porter and the Three Ladies of Baghdad for asking nosy questions while forgetting they didn't know who he was.
 * In a way,  in the Discworld books.
 * Elsewhere in Discworld, Nanny Ogg reflects on an (unrelated) story that fits this trope and her suspicion that the King in question sent his people around beforehand to make sure everyone knew what was really happening "in case anyone tried to get too common."
 * Prince Heinrich of Zlobenia in Monstrous Regiment serves in his own army as Captain Hortenz, and tries to get too common with a serving girl (actually the heroine disguised as a boy disguised as a serving girl), who naturally kicks him in the"Royal Succession".
 * When we first meet Aragorn, the rightful king, in The Lord of the Rings, he's a ranger named Strider. We don't find out his true identity for quite some time.
 * Tolkien said when he first showed up in the story he didn't know who the guy was either. Hell, the original character concept was a hobbit with wooden feet.
 * Of course, at that point in the story, Aragorn is king of nothing more than a band of nomads who spend their time keeping monsters out of Eriador and a large, rolling plain with some rocks.
 * And before the events of Lord of the Rings, there was this mysterious advisor to Steward Ecthelion (Denethor's father) of Gondor...
 * And before that, when Theoden was a child, there was a mysterious foreigner who rode with the Rohirrim and just up and left one day...
 * Prince Gwydion and Fflewddur Fflam of the Chronicles of Prydain both travel around the countryside in simple traveling garb. Both cases are heavily subverted though. The protagonist of the series, Taran, recognizes Gwydion within minutes of meeting him and is actually shocked and disappointed to not find him in more regal garb. Gwydion uses it as a lesson to not judge others by their appearance alone. Fflewddur meanwhile makes a point out of boasting how he is a king (of a rather small kingdom, but a king nonetheless), thereby voiding the "Incognito" portion of "King Incognito".
 * in The Dragons of Babel. It helps that he's been gone for a number of years and no one saw that much of him to begin with.
 * The Eternal Emperor, Ruler of the Court of a Thousand Worlds, in the Sten series by Chris Bunch & Allan Cole, liked to take a break from the Imperial rulership thing by dressing up as a seedy starship engineer named "Haroun al-Raschid" (in a deliberate homage to the Arabian Nights) and go out bar crawling. And getting in bar fights.
 * The Connatic, benign dictator of the Alastor Cluster in Jack Vance's Alastor trilogy, not only frequently goes out into the public in disguise, but makes sure that the people know of this habit. He only appears as his official self once in the series and it is implied that Ryl Shermatz, a government agent who appears in two of the books, may be one of his cover identities.
 * Sir Walter Scott's Ivanhoe features King Richard I going around as a mysterious knight searching for adventure upon his return to England. His loyal retainers' advice not to risk his life in this manner is ignored.
 * In Fiona Patton's The Painter Knight, the mildly insane king goes bar-crawling. This doesn't work, however, because members of the royal family are quasi-divine and have literally flaming eyes. Whatever tavern he enters is forced to uncomfortably maintain the fiction, under pain of having the bar burned down. When he is assassinated and his daughter and heir is on the run from her enemies, her eyes are disguised by blindfolding her with a thin cloth, so that she can see but others think she is blind. Her distinctly red hair, another family characteristic, is darkened with dirt.
 * Prince Jonathon in the Song of the Lioness quartet.
 * Prince Roger and his surviving bodyguards do this in John Ringo's We Few, literally remolding their bodies with supertech to go undercover.
 * King Arthur did this in A Connecticut Yankee in King Arthurs Court, to no one's benefit. Twain hated the monarchy. However he did give King Arthur a Crowning Moment of Awesome when he knowingly exposes himself to infection by carrying a smallpox stricken child to die in the arms of her equally ill mother.
 * The King and the Duke from The Adventures of Huckleberry Finn claim to be this, but Huck can tell they're just con men on the run almost immediately after meeting them.
 * Another Mark Twain piece, The Prince and The Pauper, features the eponymous prince swapping places with the eponymous pauper, effectively becoming this.
 * In James Thurber's The 13 Clocks, the wandering ministrel is, in reality, a prince. (The wicked duke finds him out by finding his real clothing: the Ermine Cape Effect strikes.)
 * In the Chivalric Romance Sir Orfeo, Orfeo wanders in the wilderness because of his grief at the loss of his wife, kidnapped by the king of Fairy. However, when he finds the fairy court, he exploits it to present himself as a ministrel. When the king promises him a reward, he asks for his wife back. The king objects because he is so tattered. Orfeo says that breaking his word would be worse, and gets her.
 * In Greg Costikyan's book Another Day, Another Dungeon This definitely counts as a Deus Ex Machina, but it's completely forgivable because it's hilarious.
 * In Edgar Rice Burroughs's Chessmen of Mars, Gahan the Jed of Gathol met, and rather repulsed, John Carter's daughter Tara. He disguised himself as a panthan, a wandering swordsman, named Turan when they met again.
 * Ruthlessly subverted in Yulia Latynina's Wizards and Ministers, when the naive young emperor Varnazd tries to be this . His Prime Minister was honestly relieved that this was as far as it went, haing previously noted that all the wannabe Haroun ar-Rashid emperors in the Wei Empire tended to end up as irresponsible Robin Hood-wannabe gang leaders with complete immunity from law enforcement that was afraid to arrest anyone right or wrong for the fear of accidentally arresting the Emperor.
 * 1632 has Gustavus Adolphus as in Real Life below.
 * The initial love interest in Variable Star is addicted to this in an almost literal fashion, discovering just how much she can find out if nobody realizes who she is. (She's not technically royal, but her financial status is about a step above Richie Rich.)
 * Murtagh of the Inheritance Cycle, despite seeming to be an ordinary rogue, is
 * In Andre Norton's Ruritanian novel The Prince Commands, Michael Karl, soon to be King of Morvania as a result of his cousin Urlich Karl's death, is captured by a bandit known as The Werewolf, a prime suspect, who makes no secret of his dislike for the royal family. Protests too much, methinks, because
 * In Lewis Carroll's Sylvie and Bruno, when Sylvie and Bruno chase after a beggar driven off by their uncle, aunt, and cousin, they find it's their father -- who has become the King of Elfland.
 * In Scott Westerfeld's latest novel, Leviathan,  Not a king, but close enough.
 * In the Codex Alera series, . However, it fits this trope for the fourth book, as he travels around the country as a soldier or spy rather than openly admitting who he really is. It's partly a King Incognito in the fifth book as well. The Alerans know, but to most of the Canim he is just another soldier from among the demons and he has to bargain or bully his way through. It's unlikely that knowing who he was would have affected how they treated him, though.
 * The First Lord does this as well when he feels like delivering a message personally. It's actually justified since having powerful watercrafting allows him to shapeshift. It then gets subverted in that the Genre Savvy Tavi and Marcus see right through it despite the shapeshifitng, because they know the First Lord's mannerisms and body language and the First Lord fails to change them when he's incognito.
 * Henry VII (supposedly) posed as a leper in "The King's Job" (aka The Tudor Monarchy) by Rudyard Kipling.
 * In The Malazan Book of the Fallen, a highly competent but otherwise unassuming servant turns out to be.
 * In Bernard Cornwell's Azincourt, a disguised Henry V talks to his soldiers the night before the battle. Almost certainly an homage to Shakespeare's use of the trope (see below).
 * Emperor Zakath does this in the Mallorean novels. When returning to his capital, he effectively does this simply by not having any ceremony. Since the general population of Mal Zeth only saw the Emperor as a man in expensive robes and a heavy crown, riding in a fancy carriage surrounded by a regiment of soldiers blowing trumpets, they all ignored the man in white linen riding down the street with a few friends. Later on, he plays the trope more accurately when traveling as part of Garion's adventuring party.
 * Garion also qualifies when he's adventuring.
 * In the Book of Amber, some of the Nine Princes of Amber did this, riding into shadow and taking up places away from court.
 * Paul Atreides does this in Dune Messiah.
 * In Robert E Howard's Conan the Barbarian story "A Witch Shall Be Born", Salome throws the head of a murdered man to a deaf beggar and casually discusses the true queen's imprisonment. Not only is Valerius not a beggar but a La Résistance leader, he's not deaf.
 * The Medieval Dutch epic poem Karel Ende Elegast recounts the adventures of Charlemagne, disguised as a common thief, and his companion Elegast, who may or may not be an elven king. Charlemagne takes advantage of his thieving alter-ego to break into the castle of his brother-in-law, who he then conveniently overhears plotting regicide.
 * In Anne Rice's The Mummy, the eponymous character reminisces about advising Cleopatra that a good ruler has to do this, on account of never really getting the complete picture from their advisors on the state of the kingdom.
 * In Claire Madras's "Sissi in Ireland", Empress Elisabeth of Austria-Hungary aka Sissi disguised herself as a "mere" Austrian countess to travel through a highly fictionalised Ireland of the late XIX century. Only her original hosts know who she is... but due to the gossip of their household staff, Sissi's cover is revealed to a local noble yet very simple-living Irish family that she had befriended, and who then swear secrecy.
 * Wizards in the Sword of Truth seem to make a second profession out of this. Zedd (several times), Adie, Richard (several times, never of his own volition, and invoked by the books), Ann, Nathan, Nicci (with Richard), Kahlan (in the Chainfire arc).

Live Action TV

 * In the Merlin episode "The Once and Future Queen", Prince Arthur discovers the other knights are letting him win duels and jousts, so disguises himself as an ordinary knight to compete in a tournement, to prove that he doesn't need special treatment.
 * Arguably, Merlin does this every single episode, as he is the most powerful sorcerer of all time, and he's disguised as a clumsy, slightly foolish manservant.
 * Subverted in the first season of Black Adder; Edmund, Baldrick and Percy visit a plague-ridden village to visit an informative old crone, and after several people greet Edmund, Baldrick suggests that he disguise himself so no one will deliberately infect him. Edmund then places a strip of cloth over his eye, and the peasants just play along.
 * The premise of Undercover Boss, a reality(ish) show where a CEO works in an entry-level role of his own company while in disguise.
 * In an episode of Babylon Five, Commander Sinclair goes looking for information in disguise - mainly changing out of his uniform into more nondescript clothing. Nobody recognizes him as the station commander (But then, the station does have a population of 250,000, and most of them have probably never seen his face).
 * Delenn is secretly a member of the Grey Council, keeping an eye on Sinclair.
 * Xena and a princess who look just like her had to switch places and the princess had to learn what it's like to live like a warrior peasant.
 * King Sukjong in Dong Yi likes to inspect his country in such a manner. And it was in one such tour when he bumped into the eponymous character. Hilarity ensues when she acted rather rudely (albeit not on purpose) in front of him, unaware of his real identity.
 * Trick, the bartender in Lost Girl, is secretly the Blood King of the Fae.
 * This trope is the primary conceit behind the long-running Jidai Geki series Abarenbo Shogun. The eponymous Shogun disguises himself as an ordinary samurai to hang out with firefighters, uncover corruption, and solve mysteries. Every episode ends with a Big Reveal where he confronts the evildoer of the day, which nearly always results in a big sword fight.

Myth and Legend

 * Zeus, and others of the Greek Gods would also occasionally walk the earth in the guise of old hags or beggars, so they could reward those that showed them kindness, or punish those that didn't. The most famous story of this is the tale of Baucis and Philemon, where Zeus and Hermes, disguised as beggars, are shown Sacred Hospitality by the poor, elderly couple Baucis and Philemon after their richer neighbors had shut their doors to the gods. This leads to Zeus providing some Laser-Guided Karma to the rich people and Classical Myth's Crowning Moment of Heartwarming.
 * Norse Mythology has Odin doing this a lot as well, sometimes accompanied by Loki.
 * And Japanese folklore has Youkai which fill this role.
 * According to the New Testament, God the Son became a mortal man in order to reconcile with fallen humanity, and even after his return to heaven remains The Son of Man as much as of God.
 * Some interpretations of Jesus' parable of the sheep and the goats (Matthew 25:31-46) see the King in this story as using this trope to test the goodwill of his subjects.
 * Saint Martin of Tours, one of the most popular Catholic saints, was converted after having shared his cape with a freezing beggar, who turned out to be Jesus.
 * More than one Catholic saint has an encounter like this in their legends. Saint Christopher, e.g., was an ex-Genius Bruiser turned Gentle Giant who converted to Christianity after finding out that the cute little boy once he helped cross a river was actually Baby Jesus, and that said baby was actually the Lord and Master of the Universe.
 * Both St. Francis of Assisi and St. Elizabeth of Hungary, among others, are said to have encountered Christ in the unpleasant form of a leper.
 * King Solomon, of Jewish history/mythology, was said to have been thrown down from his throne and replaced by a demon impostor. He was forced to roam the land as a commoner, so rather than by choice, this one was against his will.
 * On the other hand, the prophet Elijah favored this trick, doing it willingly to gauge the temper of the Israelite people. On the other hand, he was often forced to do it (he was hunted by King Ahab, so he had to hide).
 * Angels are said to do this, as in the story of Lot.
 * Also used by Odysseus in The Odyssey, to gain entry into Troy (as well as his home, after the suitors took it over).
 * King Alfred the Great of Wessex traditionally infiltrated the ranks of his Danish enemies disguised as a minstrel; more famously, in disguise, he was taken into a poor woman's hut and told to watch her baking cakes, and slapped by her when he burned them. (Both incidents are included by G. K. Chesterton in The Ballad of the White Horse.

Theater

 * In Gilbert and Sullivan's The Mikado Prince Nanki-Poo disguises himself as a minstrel to escape the advances of Lady Katisha, a much older woman who wants his hand in marriage.
 * A favorite of Shakespeare:
 * Several characters in King Lear.
 * In Henry V, King Henry dresses as a common soldier and wanders the camp the night before the battle so he can hear what the foot soldiers think of him. It is not always complimentary.
 * The Duke of Vienna in Measure for Measure spends most of the play disguised as a friar in order to spy on his subordinate, Angelo, who he has left in charge of governing the city. Good thing, too, since Angelo proves to be ruthless and corrupt..
 * Lucentio, son and heir of the famed merchant Vincentio, disguises himself as a language tutor in The Taming of the Shrew.
 * Played for laughs in Offenbach's La Perichole. The Viceroy disguises himself as a common man to find out what the people really think of him. His courtiers, however, have tipped off everyone in the town, and bribed them to say how much they love the Viceroy. He never catches on.

Tabletop RPG

 * In Forgotten Realms divine minions do it frequently -- Elminster more often than Khelben, and Erevis Cale constantly lives as a "head butler" of a wealthy merchant family.
 * Azoun IV Obarskyr of Cormyr, before he became king, joined an adventuring group fittingly named "the King's Men" soon after it was founded, as a swordsman named "Balin", but revealed his identity to them after a few months. The Royal Court Wizard, of course, both kept an eye on and covered for the prince, pretending he's on an expedition or pilgrimage.

Video Games
"Eirin: It was clear that Tewi wasn't just a normal youkai rabbit. All the earth rabbits listened to everything she said. Though there was nothing at all dignified in her appearance, the idea of her being able to control a great number of rabbits at will brings to mind the image of an ascetic who has achieved enlightenment."
 * In Jade Empire, the hero encounters a mysterious female ninja named Silk Fox. She later turns out to be
 * Also, Master Li of a rather small martial arts school, starts off as a somewhat important character (master of your school, but it's out in the middle of nowhere and all). Then, you find out that  It isn't a precise fit, but its quite close.
 * In the third Elder Scrolls game an old man in imperial armor gives you a lucky coin on your way to face the Big Bad if you have done certain things in the game. You never see him again, but it turns out he was the spirit of the first emperor, Tiber Septim, that had ascended to godhood.
 * The player character's history stories in Daggerfall generally involved the player helping one of the Emperor's sons without knowing who he was, and later being rewarded by the Emperor for it.
 * Three Fire Emblem games have a prince joining your party in the guise of a bard, a healer or swordsman. L'Arachel (8th game) tries to hide her identity as a princess, but enjoys drawing attention to herself too much. Other cases are Levin from the 4rth game and  from the same 8th game.
 * Radiant Dawn has
 * And, of course, from the sixth game.
 * Princess Nadia of Chrono Trigger disguises herself and takes on the pseudonym Marle in order to see the Millenial Fair. It's only after they're sucked into the past that the heroes figure out who she really is when she's mistaken for her ancestor Queen Leene.
 * More a Princess Incognito, but from Zelda, the eponymous princess, while disguised as Shiek in The Legend of Zelda Ocarina of Time, or  in The Legend of Zelda the Wind Waker''.
 * Not at first for . She has no clue about her royal lineage in the first game, but then she continues to disguise herself as her normal  persona at the end of the first and the whole second.
 * I got the impression she was having more fun as.
 * Well, would you rather be  This comic sums it up nicely.
 * Then, in The Legend of Zelda Twilight Princess, there's, who happens to be the eponymous Twilight Princess. But we don't find that out until near the end of the game.
 * Final Fantasy XII is full of these.
 * In Final Fantasy VI, by Post-cataclysmic Edgar. The heroes, having met him before, see right through the ruse. After several denials, he finally fesses up.
 * To be fair, his Paper-Thin Disguise wasn't supposed to stand up to the heroes, seeing as the disguise was supposed to allow him to hide among thieves breaking into his castle.
 * In Tales of Vesperia we have a Subversion,  thinks   this, but the only one who didn't figure out that   on his own was Karol.
 * Early on in Baldurs Gate you meet an unassuming "Old Man" in some very obvious bright red wizard getup. This being an RPG set in the Forgotten Realms and the old man's penchant for Cryptic Conversation, you should have no trouble figuring out that it's an Elminster cameo. Don't worry if you do, though -- Elminster and Drizzt have cameos throughout the entire series (when it's clear who they are).
 * One of Elminster's cameos has him taking the pseudonym "Terminsel" during Jaheira's personal quest. She figures it out quickly enough.
 * Suikoden IV: Soon after making landfall on the Island Kingdom of Obel, the Player Party is given directions to the King's place by some guy on the street wearing worn sandals and an open, salmon pink vest. Congratulations! Hello, Insert Name Here was just introduced to King Lino en Kuldes, one of the fan-favorite characters.
 * Quest for Glory 2: Trial By Fire had one when  is revealed at the end to be.
 * in Dragon Age
 * in The World Ends With You. Instead of being.
 * Roan in Grandia II, who first appears as a bratty Tagalong Kid. When the party reaches his hometown, he's revealed to be the crown prince. In the epilogue he playes the trope really straight when he ventures out of his kingdom to visit his old friends.
 * Fable III will live and breath this trope once you succeed in overthrowing the corrupt king of Albion and take his place.
 * Persona 4: Remember Well, turns out she's  And you don't find out about this unless you decide to go for the True Ending.
 * Touhou has the Earth Rabbit youkai, Tewi Inaba. As a mere Mid-Boss, fans interpreted her as a lowly servant. Indeed, based on Perfect Memento, it's assumed in-story that she serves under the Moon Rabbit, Reisen. Of course, the truth is, Tewi barely listens to anyone at all. When Reisen finally got frustrated of Tewi in Cage In Lunatic Runagate, she asks her master Eirin why they even allow Tewi to run around freely in Eientei. For whatever reason (possibly pride) Eirin doesn't tell her the truth: in reality, Tewi is the master of the Bamboo Forest of the Lost, where Eientei was built. Tewi is the leader of all the Youkai Earth Rabbits, whom only serve as Eientei's servants because Tewi says so, and wouldn't listen to the Lunarians at all otherwise. Further, Tewi is basically treating the Lunarians as tenants; she approached them long ago with the deal that she and her rabbits would help to hide the exiles from the whole world, so long as the Lunarians shared their knowledge with Tewi.


 * N from Pokémon Black and White is actually the king of Team Plasma. He reveals this to the player just before you get your fourth badge in Nimbasa City, while on the ferris wheel.
 * In Deus Ex Human Revolution,
 * of Klonoa: Door to Phantomile. You don't find this out until the last world!

Web Comics

 * The Phoenix Requiem:
 * Collar 6: Sixx admits to being a high ranking mistress, but not to being incredibly rich.
 * Impure Blood No one needs to know who I am.
 * In Strays Turns out it's Prince Holland.

Western Animation

 * Princess Jasmine in Disney's Aladdin. In fact, many a Rebellious Princess first encounters the plucky young hero this way.
 * Then when Aladdin has used his first wish, he's a commoner pretending to be a prince who was pretending to be a commoner. Think about it.
 * Done once in Transformers Generation 1.
 * The Number 9 Man of Futurama
 * Also,
 * Avatar: The Last Airbender: Hiding from his Psycho for Hire sister in enemy territory forces Zuko to trade in the role of Prince for Loveable Rogue (and occasionally Ninja-with-a-Cool Mask).
 * As we learn in the first episode of season three, this is also the intended plan for the Earth King and Bosco.
 * While it wasn't intentional on either Zuko's or Azula's part, some people didn't recognize them in one episode of Book Three and Azula quickly decided to play along.
 * Kim Possible had a prince who was threatened and so he was sent to Kim's school to blend into the student population. It worked well (well, as much as it could with the prince not disguising his arrogance), until Ron Stoppable, who didn't get the concept of "incognito" until it was too late, called the press to announce the prince's presence at Middleton High.

Real Life

 * Emperor Kangxi was famous for doing this. As was his grandson, Qianlong. In fact, these visits spawned a gesture still found in southern China. Qianlong tended to serve his companions tea and do other little things. A person receiving such a huge honour would have been compelled to kowtow (a deep, kneeling bow where one's head touches the ground) to show their gratitude, but in doing so it would have blown Emperor's cover. In order to keep the his identity secret, they developed a more discreet way to say "thank you": tapping the table several times with the knuckles or fingers, also known as the "finger kowtow".
 * Several Swedish kings have done this, particularly in The House of Vasa:
 * King Gustavus Adolphus of Sweden.
 * King Charles XI. According to folklore, his disguise was a simple grey cloak, which he would throw aside to show his royal garb at the right dramatic moment - earning him the nickname Gråkappan, The Grey Cloak. This was likely inspired by the stories of Odin incognito, which also inpired Gandalf's design.
 * The first King Gustavus. Although he did it, allegedly, while trying to escape imprisonment and execution as a rebellious noble outlaw, but still...
 * After abdicating, Christina of Sweden dressed as a man and traveled through Europe.
 * Peter the Great of Russia spent several years on tour of Western Europe, often going incognito as an ordinary worker to learn the skills he wanted to take home.
 * It's said that he never fooled anybody, since he took a posse around with him.
 * It's also said no one was fooled because Peter the Great was 6'8" and people that large aren't common today, much less during Peter's time.
 * And that he paid them well enough everyone pretended to not notice.
 * It is said that the Doges of Venice had permanent reservations at various establishments as places where they go incognito, as for a Doge to just go out for a drink like a normal person was considered unfitting to the City's dignity.
 * ...While one Polish king did leave his chambers frequently, go out for a drink incognito, get into barfights and do similar funny (if unkingly) stuff.
 * Queen Elizabeth II did this recently, to enjoy a trip in a steam train.
 * On V-E Day after the defeat of Germany, Elizabeth - then a Princess - and her sister Margaret wandered amongst the celebrating crowds amonymously.
 * There was both a Bourbon Prince and a Bonaparte prince who served in the Free French Foreign Legion during World War Two, as both their families were officially forbidden French citizenship for fear that they might cause a succession crisis.
 * Nero was said to have done this and gone around beating people up (and robbing them), in a Paper-Thin Disguise that everyone saw through but could do nothing about. After one senator beat him up anyway, he started having bodyguards follow at a distance.
 * Richard I, the Lionheart, traveled incognito after returning from The Crusades, trying to escape capture (he wasn't succesful).
 * The empress Mathilda, who had a claim to the English throne, escaped Oxford castle dressed completely in white sheets. Since it was snowing, she wasn't seen.
 * King Henry V of England. He used pseydonym "Harry Leroy" which is an incredibly lame pun on three accounts - "Harry" is colloquial for Henry, "Leroy" is a Welsh name (he was the Prince of Wales before access to throne) and le Roi means "king" in French.
 * James V of Scotland was said to wander his kingdom as "the Guidman of Ballangeich". ("Guidman" = "Goodman" = "Mister".)
 * As mentioned above, Haroun Al-Raschid.
 * Also, probably in direct imitation, Abbas the Great of Persia.
 * Harun al-Rashid was actually following the tradition of Umar ibn al-Khattab, the second Caliph, who was famous for touring whatever city he was in (usually Medina) by night more or less to check its pulse and particularly to see that nobody was being cheated and that the city's poorest weren't too poor (if they were, the Islamic pillar of Zakat--either charity or a poor-tax depending on whom you ask--wasn't working).
 * King Frederik VIII (1906-12) of Denmark died suddenly on a street in Hamburg while travelling under an alias, and had to be located and sneaked out of the public morgue by his servants.
 * After the Battle of Worcester Charles II spent six weeks attempting to flee the country (including in one instance an afternoon spent hiding in an oak tree), dressing as a regular citizen as he did so. He did usually have allies with him, who would help him move on and point to who could help him (including many Catholics, hence his general appreciation toward them later - and death bed conversion), but he also had to stand up to scrutiny to those not in the know and occasionally be almost by himself, even talking with Commonwealth supporters about that rogue Charles Stuart. He is said to have seen the time as quite character making for him.
 * What kind of character was that? From what I've read he was mainly a selfish drunken lech, whose only virtue was that he was too lazy to be a tyrant.
 * Lech, yes. Drunken and selfish, not so much. And he played the lazy thing as Obfuscating Stupidity, while actually managing to outmaneuver some of the shrewdest politicians in English history (like Shaftesbury). His brother James was much more conscientious, and much stupider, and lost the kingdom as a result.
 * Crown Prince Willem-Alexander of the Netherlands once participated in a legendary 200 kilometer ice-skating endurance race under the pseudonym W.A van Buren. After a while he got recognized, both the Queen and his father were present when he finished.
 * Sigismund of Luxemburg loved doing this. He preferred having fun over his kingly duties and often snuck out dressed as a commoner whenever he wanted to party.
 * Inspired by his predecessor's odd habit, Mathias Corvinus would occasionally travel dressed as a commoner. Rumours also claim he did some vigillante work this way. One particular story even made him into a thief, due to a fortune teller telling him that he will die the following day if he doesn't break into somebody's house - he broke into the home of one of his advisors, and came across a conspiracy to assassinate him.
 * There is a story about the Prince of Wales, the future Edward VII - a hotel in Swanage, Dorset (England) claims that he spent time travelling incognito without a retinue and arrived at the hotel only to find it full. They managed to find him a couch to sleep on - and he never let on that he was the son of Queen Victoria. That was, of course, in the days before even illustrated newspapers could print photographs of anyone, including the royal family.
 * King Bansah, a King of several tribes from Ghana works in a automobile repair shop in Germany. (Note: He also worked there before he became king. He became king because after the death of his precedessor, he was the only one of his family who could become the king according to law. So, this is also partly Unexpected Inheritance. After he became king, he wanted to continue the life as a common, and so, he stayed in Germany living a normal life while doing his work as a king.)
 * Prince Harry, younger son of Charles and Diana, once came as close to this trope as he could ever get in this day and age by participating in a "homeless for a day" event with a load of other volunteers. The half-dozen MI Bs loitering at a discreet distance probably didn't improve the already dubious authenticity of the stunt.
 * For that matter, the Prince's service in Afghanistan with the British Army might also count as this, as the government went to a lot of trouble to keep the details under wraps. It doesn't seem to have worked terribly well, as even before the story leaked he'd acquired the rather unflattering nickname of "the bullet magnet".
 * Doing this can have embarrassing results. During a visit to the theatre in the 1920s, King Alfonso XIII of Spain was unceremoniously pushed aside by a deputy mayor's bodyguard that didn't recognize him. One can only imagine his face when he got told.