A point of divergence is a specific event in an AlternateHistory BackStory that occurs differently than it did in RealLife. Most alternate history authors will change a single event, creating a "ripple effect", however, the point of divergence may range in importance and realism from a [[ForWantOfANail missing horseshoe nail]] to TimeTravel and AlienInvasion.

Alternatively, an older name for this trope is "Jonbar hinge" - a reference to Creator/JackWilliamson's ''Literature/TheLegionOfTime'', in which such an event is pivotal.
----
!!Examples:

[[foldercontrol]]

[[folder:Anime & Manga]]
* In ''LightNovel/FullMetalPanic'', the point of divergence is New Year's Eve of 1981, with everyone born on that day possessing low-level PsychicPowers and knowledge of science and technology far beyond than the current level of human progress; these people have been dubbed "Whispered". [[spoiler:The actual cause was the "Yamsk 11 Incident", wherein Russian experiments on a psychic girl named Sofia somehow gave her that advanced knowledge and [[PsychicLink mind-linked]] her to everyone born at that moment, making her the "Whisperer" who grants them that knowledge]]. This in turn spurred more changes: UsefulNotes/MikhailGorbachev was assassinated, halting his ''Glasnost'' policy, meaning the Soviet Union still exists in the early 21st century; meanwhile, Whispereds working on UsefulNotes/RonaldReagan's "Star Wars" defense initiative produced HumongousMecha, among other things.
* In ''Anime/CodeGeass'', the earliest known change from real world history is the Celts throwing the Romans out of England and winning independence some time around 1 AD[[note]]The date given for this uses the franchise's AlternativeCalendar, but other historical events mentioned roughly line up with the Gregorian calendar[[/note]]. However, even in the series' universe this is somewhat suspect; it's noted that the first historical record of this event was a book written centuries later, and there are theories that the whole thing was made up to give Britannian rulers the DivineRightOfKings.
[[/folder]]

[[folder:Comic Books]]
* In ComicBook/TheNewUniverse it was supposed to be exactly like reality until the [[MassSuperEmpoweringEvent White Event]]. The slogan was "the world outside your window."
[[/folder]]

[[folder:Film]]
* In the ''Film/SuperMarioBros'' movie, the prologue explains that the alternate reality of the Mushroom Kingdom was identical to ours until the Chicxulub meteorite impact: in our timeline, the dinosaurs were killed off; in the Mushroom Kingdom, they weren't.
[[/folder]]

[[folder:Literature]]
* In Creator/HarryTurtledove's ''Literature/{{Worldwar}}'' series, UsefulNotes/WorldWarII is interrupted by a fleet of lizard-people from outer space (a.k.a. The Race) in 1942. This is both unlucky and lucky for the aliens: if they'd shown up 50 years early they would've swiftly annihilated a planet who had yet to discover military flight, rocketry, and the basic building blocks of nuclear weapons. If The Race had shown up 50 years later they would have been soundly defeated by humans with modern technology that matched The Race but with much greater understanding of tactics and strategy, not to mention several nations having massive nuclear weapons programs.
* Another Turtledove series, ''Literature/TheWarThatCameEarly'' diverges from our timeline when the German ambassador to Czechoslavakia is assassinated by a Czech nationalist while Hitler is negotiating over the Sudetenland in 1938. This prompts Hitler to invade Czechoslovakia, with Britain and France declaring war on Germany in turn. Germany has to fight to get Czechoslovakia instead of taking it over without a fight, and as a result loses the momentum that let them take most of Europe in real life. Instead they wind up in a bloody two-front slog for most of the rest of the series. On a smaller scale, [[UsefulNotes/SpanishCivilWar Jose Sanjurjo]] in Spain listens to some good advice, leaves a bit of baggage behind, and survives the plane ride that killed him in real life. Because of the early outbreak of UsefulNotes/WorldWarII, the Spanish Republicans are saved by aid from the Allies rather than being defeated in 1939, and Spain also turns into a stalemate.
* In still another Turtledove series, the ''Literature/{{Timeline 191}}'' series, the point of divergence is right before the battle of Antietam. In the real world, a Confederate officer carelessly threw away a copy of General Lee's Special Order 191; the Union found the orders, which not only let them thwart Lee's invasion of the north but almost completely destroyed the Army of North Virginia. In Turtledove's books, the orders are recovered by a Confederate soldier instead, meaning Lee steamrolls [=McClellan=]'s army and eventually manage to capture the White House, forcing Abraham Lincoln to recognize Southern independence. This also leads to analogues for [[UsefulNotes/WorldWarI both]] [[UsefulNotes/WorldWarII World Wars]], with the USA and CSA on opposite sides.

* ''Literature/TheYearsOfRiceAndSalt'': TheBlackDeath extinguished the European civilization.
* ''Literature/SeekersOfTheSky'': UsefulNotes/{{Jesus}} was killed by Herod's troops and the Redeemer took his place as the {{Messia|nicArchetype}}h.
* In Creator/RandallGarrett's ''Literature/LordDarcy'' series, history was changed when Richard I of England was not killed by the crossbow wound he took during the siege of Chalus-Chabrol. He returned to England and John never became king. Richard died in 1219 and his son Arthur took the throne.
* L. Neil Smith's ''Literature/NorthAmericanConfederacy'' series has the divergence as the result of a single word added to the Declaration of Independence, "governments derive their just power from the ''unanimous'' consent of the governed." Somehow, as a result, the Whiskey Rebellion was successful and the entire continent became a Libertarian utopia.
* Creator/HarryHarrison uses the [[https://en.wikipedia.org/wiki/Trent_Affair Trent Affair]] as the point of divergence for his ''Stars and Stripes'' trilogy, where Prince Albert dies before helping to resolve the incident peacefully, and the British Empire attempts to invade the US, resulting in both the USA and the CSA joining forces against the largest empire in history.
* In Creator/WilliamShatner's ''Mirror Universe'' trilogy, it's revealed that the titular universe split off from the main one when Zephram Cochrane let a coin flip decide whether he would tell the Vulcans about the Borg or not. In the Prime 'verse, he hides the truth. In the Mirror Universe, he tells them, and they believe him, resulting in a much more militant union between the races in an attempt to prepare for the inevitable return of the Borg. Naturally, this is rendered non-canonic by ''Series/StarTrekEnterprise''.
* In Creator/OrsonScottCard's ''Literature/PastwatchTheRedemptionOfChristopherColumbus'', the focal point that brought our timeline into being is UsefulNotes/ChristopherColumbus receiving a vision from God telling him to sail West to convert the Asian heathens to Christ. In the original timeline, he never received the vision, instead continuing his dream of retaking the Holy Land from the Muslims. He ends up leading the most devastating Crusade of all. Meanwhile, a progressive, bloodthirsty empire rises in Central America and, eventually, takes over the world. Their descendants invent TimeTravel and sent a holographic message urging Columbus to go West. The goal of the protagonists is to create a ''third'' timeline that doesn't result in TheEndOfTheWorldAsWeKnowIt, throwing this trope out the window and going for a long-term approach.
* Averted in the Literature/WildCards series - while it ''seems'' that the arrival of Dr. Tachyon and the virus are the point of divergence for this world, there are characters like [[spoiler:Jubal / Jhubben, not a joker but an alien]] that contradict this. Also, Jetboy and Dr. Tod, two earthling characters in the origins story, already are divergences from our history. That doesn't stop people from claiming the appearance of Tach und hte virus are the first changes...
* In Creator/FyodorBerezin's ''Red Stars'' books, the parallel world's history diverges from ours mere weeks before Nazi Germany's invasion of the USSR. A British warship intervenes to aid the pockets of resistance in the Balkans against Nazi occupation, resulting in Hitler having to put Operation Barbarossa on hold in order to divert troops to put down the opposition. This, in turn, gives Stalin the chance to finish his own preparations for a BackStab and invade the German-occupied part of Poland. As a result, Germany is beaten in under two years (i.e. way before D-Day), and the USSR proceeds to "liberate" the rest of Europe. By the time 21st century rolls around, much of the world is in the hands of a powerful, militant Communist power, with North America being the only region still "free". The reason for the quotes is that the steady losses and liberal use of tactical nukes by both sides have forced the remaining nations to declare martial law and become just as militant as the USSR just to keep up. When the leaders of our world learn of this other world, they're horrified what might happen should the other world's leaders learn of ours.
[[/folder]]

[[folder:Live-Action TV]]
* ''Series/{{Sliders}}'', which deals with parallel universes on a regular basis, often has its main characters deduce the point of divergence between the universe they are currently in and their home universe (Earth Prime). In the pilot, the point of divergence between Earth Prime and the Communist-ruled USA world is the outcome of UsefulNotes/TheKoreanWar (loss for the US as opposed to a draw). In another episode, UsefulNotes/WorldWarII lasts for several years longer than expected, resulting in a different president being in office during the [[RoswellThatEndsWell Roswell incident]]. Unlike most other worlds, this guy decides to make the knowledge of aliens public, forming a trade partnership with them. By the turn of the century, the US has ubiquitous ArtificialGravity and [[WeWillHavePerfectHealthInTheFuture near-perfect health]], and an almost-successful manned mission to Mars has taken place a few years prior.
[[/folder]]

[[folder:Roleplay]]
* For the [[{{Multiverse}} major universes]] of ''RolePlay/WeAreAllPokemonTrainers'' we have the following:
** AU: Umbra getting sealed in an orb when he was the Ghost Lord, Hoenn getting flooded, Sinnoh suffering the Distortion, and Scolipede and Artemis taking over Unova.
** PMD-B: The dragons succeeding in turning 99% of humanity into Pokémon.
** Otherverse: The earliest known divergence is Grings Kodai using Azalea instead of Crown City for his Celebi plot.
[[/folder]]

[[folder:Video Games]]
* ''VideoGame/WorldInConflict''. The game asks the question, what if the Soviet Union decided to go to war in 1989 rather than face collapse? The Berlin Wall still comes down in this world, but it comes down when the Soviets blow it down with demolition charges and flood West Berlin with their troops. They proceed to [[WorldWarIII invade Western Europe]], with varying degrees of success and failure. Then they decide to launch an [[InvadedStatesOfAmerica invasion of the United States]] in the hopes of at least tricking the U.S. into pulling it's forces from Europe to reinforce the home front.
* ''VideoGame/{{Resistance}}'': The [=PoD=] occurs when Spain decides to heed U.S. demands after the destruction of the ''U.S.S. Maine'' in Havana in 1898. They agreed to give Cuba independence, averting the UsefulNotes/SpanishAmericanWar. Then the 1908 Tunguska Event brought with it in this world an alien menace, a virus that infects and turns humans into savage alien creatures. UsefulNotes/WorldWarII as ''we'' know it is averted in this world, but the aliens then invade at the end of 1949 from Russia (which had been slowly overrun in the proceeding decades.
* ''VideoGame/TurningPointFallOfLiberty'': The [=PoD=] is the death of Winston Churchill from a car accident in 1931, instead of surviving as in RealLife. Without his leadership, Britain quickly falls to the Nazis in UsefulNotes/WorldWarII. The Nazis, along with Fascist Italy and Imperial Japan proceed to conquer their areas of interest, while the Germans built up the military even more. Eventually they launch a full-scale invasion of the United States in 1952.
* In the ''VideoGame/{{Fallout}}'' series, the [=PoD=] is UsefulNotes/WorldWarII. The transistor was never invented, leading to desktop computers and robots that use vacuum tubes instead. This also had the world stuck in the social norms of the 1950's, for some reason.
* In ''VideoGame/BioShockInfinite'', the divergence point is the 1893 World Fair, or rather, the construction of the floating city of Columbia for said fair. [[spoiler:More precisely, the divergence point is the baptism of Booker [=DeWitt=], which created Father Comstock and ultimately made Columbia possible.]] In-game, Elizabeth has the power to use "tears" as divergence points to enter {{alternate timeline}}s.
* It's hard to establish where the point of divergence between RealLife and the {{Alternate Timeline}}s of ''VideoGame/ShinMegamiTenseiIV'' lies. Sometime before 2013, a suit of PoweredArmor called the Demonica was invented, and Japan's Self Defense Force purchased a large amount of them. [[spoiler:In 2013 itself, angels entered Earth from the Expanse, conspired to trigger a nuclear war, and started kidnapping innocents and God's Chosen to be spirited out of Earth when the nukes struck. In the chaos, a mysterious piece of software, the Demon Summoning Program, was dispersed through the Internet, giving some humans the chance to strike back. At the cusp of the angels' plan, with a large group of [[NukeEm ICBMs]] looming over Tokyo, a young summoner made his stand, and through his choice created three possible worlds...]]
* According to [[AllInTheManual the backstory]] for ''Enigma: Rising Tide'', the RMS ''Lusitania'' was never sunk by a German U-boat, which prevented the US from entering UsefulNotes/WorldWarI. The Central Powers win the war, with Germany annexing France and Britain. Churchill flees Britain for Hong Kong with the rest of the government aboard the HMS ''Hood'' and forms the League of Free Nations, which includes Britain's government-in-exile and Imperial Japan. The game is centered on controlling ships during this world's version of UsefulNotes/WorldWarII, a MeleeATrois between the German Empire, the US, and the LFN. The game even includes an event that is a direct parallel to the attack on Pearl Harbor, except, in this version, it's the Americans performing a sneak attack on the German fleet at Scapa Flow, with Chancellor von Richthofen (yes, [[TheRedBaron that one]]) giving a speech eerily similar to FDR's and announcing the end to the age of the battleship.
* In ''Timelines: Assault on America'', the OSS manages to assassinate Hitler in 1942, along with a number of high-ranking Nazi officials. As a result, more competent generals take charge of Nazi Germany and find out what the Americans have done. With that knowledge, they cancel Operation Barbarossa (strangely, the invasion happened the prior year in RealLife) and direct their efforts towards the US, making plans with Japan to perform a simultaneous two-pronged assault.
* In ''VideoGame/WarFrontTurningPoint'', Hitler is killed in the early days of the war, and the new chancellor is much more competent. Under his leadership, Operation Sea Lion succeeds, and Britain falls to Germany. However, this also means that Germany never attacked the Soviet Union, and the Soviets build up their forces in preparation to strike at them.
[[/folder]]
----