Oscar-nominated screenwriter Jeff Pope (“Philomena”) and Xavier Marchand of “Nautilus” producer Moonriver TV are teaming up on “Castle of the Eagles,” a six-episode limited series based on the true story of Allied POWs who staged a daring prison break from a fortified Italian castle during World War II.

The duo will be presenting the project to an industry audience in Rome during the MIA Market, which runs Oct. 14 – 18.

Written by Pope and based on the book of the same name by Mark Felton, “Castle of the Eagles” is produced by Marchand for Moonriver and Pope for his production label Etta Pictures, which is part of ITV Studios. “Harry Potter” star Jason Isaacs, who played Cary Grant in the four-part ITV biopic “Archie” written by Pope, is attached in a lead role.

The series begins in 1943, with war raging across Europe and some two dozen Allied soldiers and officers imprisoned in Castello Vincigliata, a near-impregnable fortress perched high over the Tuscan countryside that has been converted into a prison by the Fascist army of Italian dictator Benito Mussolini.

Among the prized captives are two British knights of the realm, an air marshal and 12 generals and brigadiers — some of the most senior-ranking officials to be captured and imprisoned during WWII. They’re joined by a pair of brigadiers from New Zealand, who were seized by Italian troops in Libya during Mussolini’s North African campaign.

Far from ordinary soldiers, the POVs possess some of the Allied forces’ most prized secrets — including the knowledge that the British have cracked Enigma, Nazi Germany’s nearly unbreakable code for transmitting top-secret messages. If the prisoners are transferred to Adolf Hitler’s gestapo, World War II — and the fate of Western civilization — could be hanging in the balance.

“The stakes were huge,” said Pope, who heads ITV’s factual drama division. The screenwriter, who won a BAFTA for ITV’s 2006 two-part drama “See No Evil: The Moors Murders,” said the series would not only tell the riveting tale of the POWs’ miraculous prison break — which required them to dig tunnels beneath the fortress’ walls — but explore the complex forces that were driving the war effort and reshaping the political landscape in Europe.

“It’s many things in one. It’s a thriller. It’s a psychological drama. There’s a social commentary, as well, in how it examines the Nazi and Italian captors,” Pope said. “We also look at extremism and how that can break people apart…It’s full of action and drama in the traditional sense. But underpinning it all [are broader themes] we want to explore.”

Former eOne Features president of production Marchand described “Castle of the Eagles” as “a beautiful story of male camaraderie.” “It’s a very emotional piece about older men trying to go back to the war effort,” he said. He added that the show’s creators hope to find an Italian co-producer or broadcasting partner during MIA, with an eye toward filming on location in Tuscany.

The veteran producer set up his London-based shingle Moonriver in 2016, with credits including the Lesley Manville- and Isabelle Huppert-starring “Mrs. Harris Goes to Paris,” Paramount+ and Showtime’s adaptation of Amor Towles’ best-selling novel “A Gentleman in Moscow,” and “Nautilus,” the Captain Nemo origin story inspired by Jules Verne’s “Twenty Thousand Leagues Under the Sea,” which will be released by AMC and Prime Video.

Marchand also executive produced the 2018 Laurel and Hardy biopic “Stan & Ollie,” which was written by Pope — a project that first brought the award-winning scribe together with the veteran producer.

“[‘Castle of the Eagles’] was born out of [‘Stan & Ollie’], because Xav and I spent a lot of time together working on that, which was a real passion project for both of us,” said Pope. “I think we both have a passion for the early 20th century. Even though they don’t seem like bedfellows…Stan and Ollie’s heyday was just before the Second World War. It’s an era that interests us.”

The series hearkens back to iconic WWII dramas like John Sturges’ “The Great Escape,” which starred Steve McQueen, James Garner and Richard Attenborough as Allied prisoners who stage a daring escape of several hundred POWs from a Nazi prison camp.

A key difference with “Castle of the Eagles,” however, is that most of the senior officers who broke out of Castello Vincigliata were “probably close to my age now,” according to Pope.

“Whereas ‘The Great Escape’ was young officers at the peak of their physical powers, what we had here were older men, many in their 50s and 60s, who…had something to prove to the world and to themselves about their physical powers, and how they refused to accept the fact that they were older,” he said.

“The notion of escape is something that’s fundamental to all of us. But to then have a world and characters to play with that were so unusual, and so different from other escape movies: all of that put together, I found irresistible.”