The work of fiction appears to be historical in nature, but the plot twist at the end actually derives into Alternate History. This is the important part: if the story is clearly not historically accurate, this is not this trope.
Since this is a plot twist trope, expect unmarked spoilers.
- In an odd example, the old [DC Universe DC Multiverse]] started out with Earth-1 (the Silver Age) and Earth-2 (the Golden Age) as basically exact duplicates of the real world timeline for major historical events, but with added superheroes. Later on, though, writers introduced casual historical divergences in stories set on Earth-2, such as a single panel rather pointlessly revealing that its South Africa had ended apartheid in the 1970s. At the time the story was published, this hadn't happened in the real world or on Earth-1.
Live Action TV
- Blackadder did this occasionally. In one episode, Baldrick accidentally burns the manuscript of Dr Johnson's dictionary, realises he's actually burnt something else, then ends up deliberately burning the real manuscript anyway. In fact, every series of Blackadder uses this, usually in the finale, as a major plot point.
- The first episode of ''Blackadder' starts out as a humorous version of the Battle of Bosworth field, but then has Richard III actually win only to die when the title character accidentally kills him. The finale of the first season then explains how the historical record we have was actually created.
- The second Season Finale has a tag in which the evil Prince Ludwig returns and kills the entire cast, including Queen Elizabeth, and then rules England for the rest of Elizabeth's recorded reign while disguised as her.
- Blackadder III ends with Edmund Blackadder replacing the now-dead Prince Regent, George IV, The imposture is aided greatly by the madness of George III and the episode's successful Zany Scheme to deceive the Duke of Wellington.
- Blackadder Goes Forth shockingly ends by averting the twist from previous seasons after teasing it. For a moment, it looks as if the cast are to be spared, because the First World War has ended. Then Percy gives the date, a year before the actual armistice, and the viewer realizes that no twist is coming. instead, the characters are all killed when they are sent "over the top."
- In the film Inglourious Basterds, we're led to believe that the Basterds' attack on the Nazi high command, including Adolf Hitler, will ultimately fail, because in the actual historical record, Hitler commits suicide in his bunker in Germany. But in the climax of the movie, Omar and Donny ultimately kill both Hitler and Goebbels as the theater burns down.
- An in-universe example in Star Trek: Enterprise: one episode begins with a flashback to the scene in First Contact where a Vulcan spaceship first lands on earth. However, instead of the peaceful greeting that happened in the film, the humans shoot the Vulcan and storm the ship. The episode is set in the Mirror Universe.