* Almost all of Creator/WilliamShakespeare's plays are based on pre-existing works, legends, and historical figures. Out of all his plays, only ''Theatre/TheTempest'' seems to be an original plot by Shakespeare.
** ''Theatre/RomeoAndJuliet'' was an adaptation of an Italian narrative poem called ''The Tragical History of Romeus and Juliet'', which had been translated into English about thirty years before Shakespeare's play. The poem's basic story is itself very similar to Creator/{{Ovid}}'s "Pyramus and Thisbe" in ''Literature/TheMetamorphoses'' from Myth/ClassicalMythology.
** ''Theatre/TitusAndronicus'' bears many similarities to another myth Ovid recorded: the story of Philomena. Lavinia actually grabs a copy of ''The Metamorphoses'' to tell her family what had happened to her.
** ''Theatre/{{Othello}}'' was taken from Italian author Cinthio's short story "Un Capitano Moro", in his anthology ''Gli Hecatommithi''. In the original story, the Moor gets away with his crime for a while, Iago's motive is lust over Desdemona, and the moral is that European women should not fall in love with foreigners.
** ''Theatre/{{Macbeth}}'' was taken from stories Shakespeare found in Raphael Holinshed's ''Chronicles of England, Scotland and Ireland''.
** ''Theatre/{{Hamlet}}'' was based on a legendary Danish prince of the same name. Scholars also suspect that Shakespeare's play was an adaptation of a previous play based the legend. No copies of the "''Ur-Hamlet''," if it ever existed, have survived.
** ''Theatre/KingLear'' and ''Theatre/{{Cymbeline}}'' were taken from Geoffrey of Monmouth's ''Literature/HistoriaRegumBritanniae'', a 12th-century pseudohistorical text.
** ''Theatre/TheComedyOfErrors'' is based off of ''Menaechmi'' by Plautus.
** ''Theatre/TheTempest'' was inspired by an actual shipwreck caused by a hurricane; the description of Bermuda, where the victims landed, just sounded that cool to English audiences.
* While Creator/{{Shakespeare}}'s ''plots'' might not be as original as people think, his use of language certainly was, and that leads to this trope in and of itself, or its opposite, NewerThanTheyThink. As quoted in ''The Story of English'':
-->''If you cannot understand my argument, and declare "It's Greek to me", you are quoting Shakespeare; if you claim to be more sinned against than sinning, you are quoting Shakespeare; if you recall your salad days, you are quoting Shakespeare; if you act more in sorrow than in anger, if your wish is father to the thought, if your lost property has vanished into thin air, you are quoting Shakespeare; if you have ever refused to budge an inch or suffered from green-eyed jealousy, if you have played fast and loose, if you have been tongue-tied, a tower of strength, hoodwinked or in a pickle, if you have knitted your brows, made a virtue of necessity, insisted on fair play, slept not one wink, stood on ceremony, danced attendance (on your lord and master), laughed yourself into stitches, had short shrift, cold comfort or too much of a good thing, if you have seen better days or lived in a fool's paradise - why, be that as it may, the more fool you, for it is a foregone conclusion that you are (as good luck would have it) quoting Shakespeare; if you think it is early days and clear out bag and baggage, if you think it is high time and that that is the long and short of it, if you believe that the game is up and that truth will out even if it involves your own flesh and blood, if you lie low till the crack of doom because you suspect foul play, if you have your teeth set on edge (at one fell swoop) without rhyme or reason, then - to give the devil his due - if the truth were known (for surely you have a tongue in your head) you are quoting Shakespeare; even if you bid me good riddance and send me packing, if you wish I were dead as a door-nail, if you think I am an eyesore, a laughing stock, the devil incarnate, a stony-hearted villain, bloody-minded or a blinking idiot, then - by Jove! O Lord! Tut, tut! for goodness' sake! what the dickens! but me no buts - it is all one to me, for you are quoting Shakespeare. (The Story of English, 145)''
* Unlike the stereotypical musical comedy, ''Theatre/{{Oklahoma}}'' doesn't use the standard OpeningChorus; its opening number is a solo. But neither did half of the musical comedies that came before it; in fact, many of them didn't have an opening number of any sort, unless you count the short passage of nondescript music the orchestra plays while the curtain opens on a scene of expository dialogue. (And though ''Oklahoma!'' was indeed the first Rodgers and Hammerstein musical, they had first collaborated in 1919, when their careers had barely started.)
** Also, while ''Oklahoma!'' tends to get credited as the first truly story-driven musical, with songs closely tied to the desires and actions of their characters rather than just examples of ThatRemindsMeOfASong, there are older examples out there; ''Theatre/ShowBoat'' is probably the most famous. Even the film musical ''Disney/SnowWhiteAndTheSevenDwarfs'' (1937) can be counted among these.
* Fans of ''Theatre/{{Rent}}'' and ''{{Theatre/Dreamgirls}}'' cried TheyChangedItNowItSucks when some of the lyrics were converted to spoken dialogue in the movie versions. Not many people know it, but the spoken dialogue leading into the second act finale of ''Theatre/HMSPinafore'' was originally sung as a recitative.
** The story of ''Theatre/{{Rent}}'' is itself OlderThanTheyThink, being essentially the story of ''Theatre/LaBoheme'' by Puccini. Puccini's MadameButterfly was updated and set in the Vietnam War for the sake of ''Theatre/MissSaigon''.
* Though Broadway musicals almost never used screenplays as source material before TheFifties, there was a musical in 1919 based on a silent movie.
* A Broadway musical about cats, based on a series of poems, and with considerably more dancing than plot? ''Shinbone Alley'', which opened 25 years before ''Theatre/{{Cats}}''. However, ''Shinbone Alley'' failed to put its cats in any kind of cat costumes, which may help account for its far shorter run.
* An unusual choice of source material for a musical, stuck in previews, ends up abandoned by its original writer due to horrible reception. Bono and The Edge wrote the songs. The show in question? ''Literature/AClockworkOrange: TheMusical'', 20 years before ''SpiderMan: Turn Off The Dark''.
* It's no secret that the songs in ''Theatre/MammaMia'' are just recycled Music/{{ABBA}} hits, but the plot isn't exactly original, either: the 1968 film ''Buona Sera, Mrs. Campbell'' used largely the same plot, as did ''Carmelina'', a 1979 Broadway musical flop by Alan Jay Lerner and Burton Lane.
** {{Jukebox Musical}}s using the back catalogs of songwriters/musicians or a passel of songs from a certain era also date back decades on both the stage and the big screen. ''Film/SinginInTheRain'' is one example! ''Mamma Mia!'' was the first international megahit based around a ''pop'' song catalog, but London's West End had already seen several such shows prior to its 1999 opening, such as ''Buddy'' (the Buddy Holly back catalog) and ''Return to the Forbidden Planet'' (early rock hits).
* The 1994 stage adaptation of Disney's ''Disney/BeautyAndTheBeast'' wasn't the first "legit" ScreenToStageAdaptation from the Franchise/DisneyAnimatedCanon. ''Disney/SnowWhiteAndTheSevenDwarfs'' had ''several'' stage adaptations in varying cities/venues long before that, including a 1979 version that ran as a limited engagement in New York City at the huge Radio City Music Hall and had the same scope and scale as later Disney stage musicals -- a videotaped version was even one of Disney's early [=VHS=] releases.
* In ''{{Theatre/Godspell}}'', many of the lyrics that aren't from Literature/TheBible are from old hymns and prayerbooks.
* One thing that practically ''everyone'' knows about 17th century English theatre is that women were banned from stage acting, forcing men to play female roles. While this is certainly not wrong, comparatively few people seem to know that the ban on female actors was lifted during the reign of Charles II, which began in 1660--less than half a century after Creator/WilliamShakespeare's death. Out of the 400-odd years that Shakespeare's plays have been performed, women have been allowed to play the female roles in them for roughly 350 years.
* Many people believe "I Feel Pretty" from ''Theatre/WestSideStory'' is [[{{Bowdlerise}} frequently censored]] to avoid HaveAGayOldTime. It's the other way around. "I feel pretty and witty and gay" is the censored version while the original is "I feel pretty and witty and bright". The lyrics were changed because the song was moved to an earlier scene than in the stage version and possibly to avoid implications of sex: "bright" rhymed with "tonight" instead of "today".
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