[[quoteright:350:http://static.tvtropes.org/pmwiki/pub/images/466px_ali_baba.jpg]]
[[caption-width-right:350:Kasim is stumped.]]

->"Open sesame!"

"Ali Baba and the Forty Thieves" is a story from the ''Literature/ArabianNights''.

Ali Baba, a poor woodcutter, stumbles on the treasure cave of a band of robbers, which is magically sealed and must be opened by speaking the words "Open Sesame". He takes some of the treasure from the cave and becomes rich, but his brother Kasim, a greedy merchant, discovers this new wealth and demands to know the secret of the cave. Unfortunately, once inside he forgets the magic password to open the door, and subsequently he is discovered by the robbers and killed. They cut his body into quarters and hang it up at the entrance to the cave. Ali Baba finds his brother's body, and buries him, doing what he can to disguise the cause of death, but the robbers realize that someone else has discovered their hiding place. Their attempts to identify Ali Baba and kill him are repeatedly foiled by a clever slave-girl named Morgiana, and all the thieves wind up dead. Morgiana marries Kassim's son, Ali Baba makes Kasim's widow his second wife, and the family lives happily ever after.

Although the story is best-known as part of the Arabian Nights, and is one of the best-known stories from the Arabian Nights, it appears to be a late ring-in. The earliest existing written version is in the first European translation of the ''Arabian Nights'', published in the 18th century by Antoine Galland, and it's thought that he included the tale from a separate source.

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!!This story provides examples of:
* ActionGirl: Morgiana is a borderline case. She personally kills 38 of the 40 thieves, and her last kill is up close and personal, with a knife.
* AssholeVictim: In some versions Kassim bullies or blackmails Ali Baba into revealing the secret of the cave. You don't feel to sorry for him when he meets his fate.
* BigBad: The chief bandit of the 40 Thieves.
* BlindfoldedTrip: Morgiana does this with Baba Mustafa the tailor, leading him to Kasim's house so Mustafa can stitch Kasim's body back together. This precaution fails when the bandits arrive to seek Ali Baba -- on three separate trips the blindfolded Mustafa successfully retraces his steps to lead the bandits to Kasim's house, where Ali Baba is now living.
* CanonImmigrant: As noted above, this tale was not included in any of the ancient manuscripts that make up the ''Arabian Nights'' and in fact there is no source for it before Antoine Galland included it in his early 18th-century translation of the ''Arabian Nights'' into French.
* CharacterNameAndTheNounPhrase
* DeadGuyOnDisplay: Poor Kasim, chopped up in quarters and hung outside the door to the cave as a warning.
* DecoyProtagonist: Ali Baba is the protagonist at first, but he pretty much stops being such after he recovers Kasim's body; at that point, the story belongs to Morgiana, with Ali Baba now a supporting character.
* DesertBandits: The 40 thieves rob caravans then place the bounty in their magic cave.
* FakingTheDead: An odd case where the victim truly is dead but the ''manner'' of death needs to be faked. Kasim's household spends two or three days building the ruse that their master is desperately ill, so when he is finally pronounced 'dead' it raises no suspicion.
* FamilyUnfriendlyDeath: In order to infiltrate Ali-Baba's house the chief bandit poses as an oil merchant and hides his men in large oil jars. (One of the jars actually does contain oil, to keep up the ruse). When Morgiana discovers the hiding bandits, she dispatches them all by heating the oil to boiling and pouring it over them.
* {{Greed}}: Kasim's FatalFlaw. He apparently intends to loot the whole treasure cave in one take, lingers too long and forgets the password.
* GuileHero: Morgiana.
* HeKnowsTooMuch: At first, this is the reason why the Bandit Chief devotes so much time to finding and killing Ali Baba, to keep the location of his hoard a secret. (When all his men are dead, however, it becomes a matter of self-preservation.)
* NeedleInAStackOfNeedles: One of the thieves learns the location of Ali Baba's house, and puts a mark on his door. While he's away fetching the rest of the thieves, Morgiana sees the mark, and thinking quickly she puts the same mark on every other door in the street. A second thief tries to mark the door more surreptitiously, but Morgana notices the mark anyway and does the same thing. The leader of the thieves is smarter, however, and chooses to study the house and area until he memorizes the location.
* OpenSesame: The TropeNamer. Also requires a "Shut Sesame" upon leaving the cave.
* SacredHospitality: A dinner guest at Ali Baba's house says that he is unable to eat salt; his excuse is a dietary restriction, but actually he's the bandit chief, come in disguise to kill Ali Baba, and if he eats salt while he's a guest, he has "shared salt" with his host and is bound by the laws of hospitality. Clever Morgiana quickly figures out that this man is up to no good.
* SlaveLiberation: Ali Baba frees Morgiana after she saves his life multiple times.
* SpannerInTheWorks: Ali Baba's cover is blown when Baba Mustafa, the tailor, brags to a stranger that he is so skilled he can sew a human body back together. Later, Kassim's son unwittingly brings the bandit chief into Ali Baba's home.
* SpellMyNameWithAnS: Depending on the version of the story, Ali Baba's brother is either spelled "Kasim", "Cassim", or "Kasym".
* StandardHeroReward: Ali Baba marries his nephew to Morgiana as a reward for her heroism.
* StupidEvil: The Forty Thieves are obsessed with finding Ali Baba to silence him, and just don't know when to quit. They spend a fortune to find the place (as the tailor gets smart and charges a larger fee each time) two of them are killed by the leader for messing up, and when they finally ''do'' find his house, ''all'' of them but the leader are killed in the attempt. But the leader ''still'' doesn't give up, and his final attempt gets ''him'' killed. Relocating and setting up shop elsewhere may have been the smart thing, but they clearly lacked smarts.
* TreasureRoom: The thieves' cave.
* TryEverything: Ali Baba's brother Kasim attempts his own raid on the thieves' cave, but forgets the password, attempting several different kinds of grain without recalling the right one. "Open Barley?"
* WomenAreWiser: Kassim's wife discovers Ali Baba's new treasure; Morgiana foils all of the thieves' attempts to harm him. Meanwhile, Kassim forgets how to exit the cave, and Ali Baba never once realizes his life is in danger until Morgiana's already saved him.
* YouHaveFailedMe: The bandit leader kills two of his men who volunteer to find the house and mess up. (See NeedleInAStackOfNeedles, above.) Then he wises up and decides to do it himself.
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