Game of Thrones spinoff writer likens Aegon's Conquest series to 'doing Napoleon or Alexander the Great'

Screenwriter Mattson Tomlin has his hands in a number of high-profile geek properties. He's the creator and showrunner behind the Terminator anime series coming to Netflix, he's scripting the sequel to the Robert Pattinson-fronted The Batman, he's attached to movies based on the Mega Man video games and the Keanu Reeves comic book BRZRKR, and now the Romanian-born filmmaker is writing a treatment for a new Game of Thrones spinoff.

Tomlin briefly addressed the latter in an interview with Entertainment Weekly about Terminator: Zero. "That one is very early days where I'm currently writing the script, currently doing a lot of great back and forth with George," he says of collaborating with A Song of Ice and Fire author George R.R. Martin.

HBO has not formally greenlit the spinoff, but the concept is about Aegon Targaryen, a.k.a. Aegon the Conqueror, the storied ruler who flew on dragonback from the land of Old Valyria, waged a campaign to unite the Seven Kingdoms, and became the first king of Westeros. Tomlin is largely working to adapt material chronicled in Martin's 2018 book Fire & Blood, which was written as if it were a real historical document on the Targaryen dynasty.

"In speaking to George, it became really clear, 'This is history, treat this like it is what happened,'" he explains. "Unlike the original series, I don't have thousands of pages to go off to adapt. I've got a couple hundred that I'm really focused on, and in those pages of Fire & Blood, there are a lot of clues. It kind of turns into doing Napoleon or doing Alexander the Great or doing some great historical figure where we know a lot about the guy. We know where he was, we know who he conquered, we know who lived, and we know who died. That all becomes the plot, and then it becomes my job to go, but what did it mean thematically? How did it feel? What were the emotions when this person died and this person lived? We don't have the context. We don't know what anybody said."

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Multiple other spinoffs are in the early development stages, but the only two that have been officially approved are House of the Dragon, the Emma D'Arcy- and Olivia Cooke-led prequel about the Targaryen civil war known as the Dance of the Dragons; and A Knight of the Seven Kingdoms, about a squire-turned-knight named "Dunk" (Peter Claffey) and his diminutive companion "Egg" (Dexter Sol Ansell). But House of the Dragon already expanded on the lore of Aegon the Conqueror in its first season.

Those who watch the Golden Globe-winning drama will remember how Paddy Considine's King Viserys Targaryen shared a story with his daughter, Rhaenyra (played by Milly Alcock in the character's younger years). The reason Aegon felt compelled to unite Westeros under one rule is because he had a prophetic dream about an endless winter coming from the North to cover everything in its path. He believed humanity's best defense was to have a Targaryen with the power of dragon fire at their disposal on the throne. Aegon, who we know in hindsight was predicting the Great War with the white walkers, called this vision A Song of Ice and Fire, the name Martin gave to his book series that inspired HBO's Game of Thrones.

Ryan Condal, who co-created House of the Dragon and serves as its showrunner, confirms to EW that he's at least somewhat involved in the Aegon's Conquest series. “People are picking my brain all the time. It's very early days, but we shall see," he says. Condal is also executive producing A Knight of the Seven Kingdoms.

Meanwhile, House of the Dragon season 2 premieres on HBO and Max on June 16. Read more in EW's Summer TV Preview cover story.

The above illustration is reprinted from The Rise of the Dragon: An Illustrated History of the Targaryen Dynasty, Volume One by George R. R. Martin, Elio M. García Jr. and Linda Antonsson. Copyright © 2022 by George R. R. Martin.