The Empire is the lone global superpower and The Kingdom is a tiny but resource-rich speck of land on the other end of the globe. Everybody believes that The Kingdom was a real threat so The Empire was justified in attacking it.
The empire considered what they did right at the time but shifting values make their descendants feel very guilty about it. They scour the earth for overlooked evidence and put together the damning history of what really happened .
Double Subverted: ...except, that historical evidence was also forged.
Just because they can, the imperial historians write that The Kingdom was populated by one-legged, two-headed people with flowers for hair who fought with golf clubs.
Zig Zagged: The Empire sets out to rewrite history, but their blatant lies spark off a rebellion and lead to a coup. Following this upheaval, the rebel leaders glorify themselves and vilify The Empire. Most citizens are aware of this, but don't care because they hated The Empire anyway. ...However, eventually some of the nastier things the rebels did to defeat their enemies come to light, including acts that make them Not So Different. This creates a rift between those demanding the full truth be told and those who prefer to ignore those travesties because they ultimately benefited from them. This leads to another revolution, the former heroes are overthrown, and these rebels set out to ensure their image remains clean...
Averted: The history of a conflict is written by an impartial observer (possibly by an even stronger superpower).
Lampshaded: "History is written by the winners, remember?"
Invoked: "History will be kind to me, for I intend to write it."
Exploited: The Protagonist doesn't care if they have to slaughter everyone in that Village to get the Spy, because if the Empire said that they found the Village already slaughtered nobody would believe them.
Defied: "This folder contains the full truth I discovered about the war. Over five hundred such folders are currently on the way to every major publishing house in the world."
Discussed: "If we die now, his truth will be the only one remaining."
Conversed: "I mean, what's the point of fighting in the first place, if they cannot win and will be remembered as villains for all eternity thanks to the winners' propaganda?"
Deconstructed: The Empire tries to rewrite the history of a recent war but its citizens lose patience at such blatant lies and spark a rebellion.
Reconstructed: ...after the coup, the rebel leaders glorify themselves and vilify the previous government even further.
Played For Laughs: The Kingdom is treated as having the stuff of a joke.