How The Lord of the Rings: The War of the Rohirrim adapts two pages of Tolkien lore into a whole movie

The Lord of the Rings: The War of the Rohirrim is a fascinating experiment in adaptation. It's not adapting a novel of J.R.R. Tolkien's, but rather two pages from his Appendices, which lay out the last great stand of one of Rohan's most famed kings, Helm Hammerhand (voiced by Succession's Brian Cox).

In this section of the Appendices, Tolkien writes that a rival lord named Freca (voiced by Shaun Dooley) proposed that his son Wulf (voiced by Luke Pasqualino) marry Helm's daughter. Not only does Helm reject the proposal outright — he also kills Freca with one mighty punch. (His name is Hammerhand for a reason.) Wulf vows vengeance and spends the next few years assembling a mighty army. Then, he takes the city of Edoras, and pushes Helm and the Rohirrim back to the Hornburg, where a long, cruel siege awaits.

It's a great story, one that sees Helm singlehandedly terrorizing Wulf's men until his very last breath. But to make it into a full-length film, screenwriters Phoebe Gittins and Arty Papageorgiou (who took over from original writers Jeffrey Addiss and Will Matthews) had to make some changes from the original text, expanding on it in some places, and cutting it in others.

To learn more about The War of the Rohirrim's adaptation process, Mashable spoke with Gittins and Papageorgiou about the choice to center Helm's daughter Héra (voiced by Gaia Wise), the role of The Lord of the Rings' Éowyn (Miranda Otto, returning in voiceover) as narrator, and more.

Helm's daughter Héra — unnamed in Tolkien's work — takes the lead in The War of the Rohirrim.

While you might think two pages of fictional history isn't a lot for writers to draw from, Gittins and Papageorgiou disagree.

"It's actually so dense," Papageourgiou told Mashable in a Zoom call alongside Gittins.

Gittins added: "It's Tolkien! The strength of his world-building means there's always going to be a thread that pulls another thread that pulls another thread."

One of the threads from the original text The War of the Rohirrim pulls on is that of Helm's unnamed daughter, mentioned just once in Tolkien's writing. ("Do not look for tales of her in the old songs," Éowyn tells us in her opening narration. "There are none.") It was producer Philippa Boyens, who co-wrote The Lord of the Rings movies and is also Gittins' mother, who suggested that the film dive into what her story might look like. After all, the conflict between Wulf and Helm starts as a result of a marriage proposal involving her.

"We felt Tolkien really did place her at the heart of this conflict," Gittins said. "It is her story in large part. A lot of this war is because of her. And once we got our heads around that, it became very exciting to see what we could do with this character, and see what we could bring to the table with her."

Héra's involvement allows The War of the Rohirrim to further flesh out Helm's dynamic with his own family, as well as pay tribute to Rohan's shieldmaidens. But it also solves a bit of a logistical problem in terms of how to carry The War of the Rohirrim forward following Helm's final sacrifice.

"When you look at the text, you know the fate of Helm Hammerhand. You know it's epic, and it's tragic, and it's iconic, but it didn't really give us an ending," Gittins explained. "The value at stake, the Rohirrim, are still behind those walls in the Hornburg. You can't just leave them there. So who can see this story through for us?"

The answer became Héra, the only one of Helm's children whose fate is left uncertain in the Appendices. Bringing her to the forefront allowed The War of the Rohirrim to explore a new kind of warfare in the latter part of its siege sequence.

"We get to see the defense of the Hornburg from a nontraditional general or leader or commander," Papageorgiou said.

The War of the Rohirrim shows us a different kind of attack on the Hornburg — with some callbacks.

The War of the Rohirrim is not the first time Lord of the Rings fans have seen the Hornburg under attack. That honor falls to the Battle of Helm's Deep in The Two Towers, a sequence so monumental that anything remotely resembling it has some big shoes to fill.

"That is untouchable in the films," Gittins said.

So how would The War of the Rohirrim bring something new to an attack on the Hornburg? By focusing in on the brutal, months-long attrition of the siege. (For comparison, the Battle of Helm's Deep lasts one night.) As the Long Winter rages on, Helm leaves the Hornburg nightly and fights his way through parts of Wulf's camp. Meanwhile, Wulf has his men build a siege tower that will eventually breach the walls of the keep.

"It was exciting for us to go into that space in a deeper way," Gittins said. "What we found really cool was that there's suffering on both sides in the stalemate, and at some point it's going to break. There is this great horror that begins to unfold where the Rohirrim are seeing their impending doom."

"There's this sense of a ticking clock," Papageorgiou added.

Wulf's presence at the Hornburg is a deviation from Tolkien's work, where he remains on the throne in Edoras until his defeat at the hands of Helm's nephew Fréaláf (voiced by Laurence Ubong Williams). Here, though, his vengeance drives him to pursue Helm and Héra all the way to the Hornburg himself, intensifying the standoff. It also brings the final clash between Fréaláf and Wulf's men to the Hornburg, instead of leaving it in Edoras.

Fréaláf and his army's arrival at the battle echoes Gandalf and Éomer's arrival at Helm's Deep in The Two Towers — they even ride down the same hill! Meanwhile, Héra's idea to distract Wulf with a duel (a new addition to the story) calls to mind a smaller scale of Aragorn's plan to draw Sauron's eye away from Frodo in The Return of the King. But these aren't the only references to the original Lord of the Rings trilogy that Gittins and Papageorgiou added to The War of the Rohrrim.

The War of the Rohirrim brings Éowyn back ... as a narrator.

Tolkien's appendices are presented as straightforward histories. The War of the Rohirrim adds a twist to that by presenting its story as a tale told by Éowyn. It's a fitting choice, given that Héra is basically Éowyn 2.0. Both are headstrong daughters of Rohan's king during a time of crisis, each desperate to help their people even when their fathers' protectiveness may hold them back.

"We knew we would need to draw inspiration for [Héra] from somewhere, and we asked ourselves the question, 'Who would have paved the way for the likes of Éowyn?'" Gittins said. "So it just felt like a really natural fit, given that we'd drawn so much inspiration from Éowyn to Héra, that we use Éowyn as a narrative device as well."

Éowyn's narration frames the film as a story passed down through generations, in a choice that Papageorgiou said "spoke to the storytelling aspect of the Rohirrim culture."

There's an added layer of myth-making here. Since this tale is now legend, any of its exaggerations or deviations from Tolkien's text could simply be viewed as the legend warping and changing with each telling.

How does The War of the Rohirrim fit into the wider context of Middle-earth?

Éowyn isn't the only familiar face — or really, voice — popping up in War of the Rohirrim. Saruman (voiced by the late Christopher Lee in a line taken from archival footage) makes an appearance at Fréaláf's coronation, just as he does in the Appendices. But we also get a hint at another wizard from The Lord of the Rings: Gandalf. He writes to Héra at the end of the film, hoping for more information about the orcs she encountered stealing rings behind the Hornburg.

Gandalf's inclusion was another idea of Boyens', in an effort to gesture out to the wider world of Middle-earth, and also provide a counterpoint to Saruman's cameo. "If you're going to introduce the dark, you have to introduce the light as well," said Papageorgiou. "You can't have Saruman without Gandalf."

The wizards are just some of many Lord of the Rings details Gittins and Papageorgiou incorporate into War of the Rohirrim. Also present are the ring-stealing orcs, the Great Eagles, and a runaway Mûmakil (or Oliphaunt), each a hint at the war to come, as well as proof of Tolkien's vast, interconnected legendarium.

"Even the smallest detail will launch a geopolitical rabbit warren of investigation," Papageorgiou said. "That's actually the hard part. It's not a question of, 'How did you make this number of paragraphs into a feature film?' It's more, 'Well, how didn't we make six films?'"

The Lord of the Rings: The War of the Rohirrim is now in theaters.