When I pitched One Woman’s War: A Novel of the Real Miss Moneypenny in October 2020, I had no idea that Operation Mincemeat, a movie about the same subject matter, would be released in early 2022, just a few months before One Woman’s War was due out.

Both fictional works are based on a real British Naval Intelligence operation of World War II, where a corpse dressed as a royal marine was left in waters off the coast of Spain. The deceased marine carried papers suggesting that the European invasion would take place via Greece, rather than the true landing point of Sicily. Spoiler: German spies got hold of the documents and Hitler fell for the ruse, diverting troops from Sicily to Greece. Many thousands of Allied lives were saved as a result.

There have since been several retellings of this eccentric operation. The truth has all of the trappings of a good, old-fashioned spy story, perhaps because the mastermind behind it was destined to become one of the best-known thriller writers of all time: James Bond author Ian Fleming. When real events unfold like fiction, it becomes the task of the fiction writer to make those real events seem plausible. But do authors of historical fiction have a greater duty to readers not to stray too far from the truth than filmmakers have to their audiences?

Avid readers of historical fiction seem to demand historical accuracy in every particular—or at least in the particulars in which those readers, themselves, happen to be experts. Yet even the keenest historical pedant has low expectations of anything out of Hollywood. These movies exist to entertain not teach.

However, people do expect greater adherence to the facts in novels. They want to experience history. Readers of historical fiction want to see events unfold through the protagonist’s eyes and feel the characters’ emotions. Whether they are conscious of it or not, historical novel readers crave a narrative that has conflict, meaning, and some sort of dramatic arc, even though real life might have a lot of the first and none at all of the second and third.

In the case of Operation Mincemeat, fortunately for screenwriters and authors alike, the bare facts of the strategic effort provide a strong plot. Still, a little creative intervention was needed at certain points to turn those facts into a novel.

A common problem I see in war novels occurs when a significant part of the action takes place in theaters in which none of the main characters are present. This is particularly difficult when writing from a first-person or close-third-person point of view.

Historical novel readers crave a narrative that has conflict, meaning, and some sort of dramatic arc, even though real life might have a lot of the first and none at all of the second and third.

There were two aspects to this problem for Operation Mincemeat. The first was a lack of direct, active conflict with the enemy when all of the planning for the operation took place in London. The second was that the events unfolding in Spain and Germany needed to be conveyed to the audience somehow, even though the main characters didn’t witness them.

Both the filmmakers and I chose to depart from the facts here and create a story thread that brings the enemy to London in some form—mine is in the guise of another point-of-view character, an Austrian double agent based in London, who is given the task of verifying the intelligence from the corpse and reporting back to German high command. In the movie, the enemy comes to London in the form of the bartender at the Gargoyle Club who claims to be working for a disaffected group from German military intelligence.

As for the action that takes place in Spain and Berlin, in the film, the story briefly shifts to Spain and is told from the point of view of a character we haven’t seen much of until that point—a technique a novelist would find far more difficult to get away with. I decided to convey the same information in an active—though not historically accurate—way, sending my Austrian double agent first to Portugal, then to Berlin, where she could be privy to Nazi intelligence gathering and analysis.

The final and greatest challenge when writing about Operation Mincemeat was imagining personal stories and conflicts for my main characters. The filmmakers, too, added private difficulties for the characters that jeopardized the operation, although they were very different from the problems I created.

While filmmakers tend to be forgiven far more easily for taking liberties with historical facts, we novelists do have the advantage over filmmakers in one respect: a magical thing called the author’s note, where we can explain ourselves—and beg most humbly for the forgiveness of our discerning readers.

Christine Wells is the author of Sisters of the Resistance and One Woman’s War.