Since Game of Thrones ended in 2019, HBO has created a couple of spinoff projects: House of the Dragon is currently between its second and third seasons, and a new spinoff called A Knight of the Seven Kingdoms will air early next year.
They've been quietly working away on other projects in the background, although none of them are guaranteed to actually make it to screen. The one that seems the closest is a show about Aegon Targaryen's conquest of Westeros, which he carried out with his sisters Visenya and Rhaenys some 300 years before the events of Game of Thrones. Mounted on their dragons and joined by only a small army, the three of them managed to bring all Seven Kingdoms to heel and unite them under Targaryen rule.
Well, they weren't able to conquer Dorne, a detail that may get explored in this new show. To write it, HBO has tapped Mattson Tomlin, who has shot up quickly in the ranks of high-powered Hollywood writers. Last month, he celebrated finishing work on the script for The Batman: Part II, which he co-wrote with director Matt Reeves. And then just the other day, he shared a cute little GIF of a dragon spewing fire at a tower, which recalls an adorable version of Aegon's dragon Balerion the Black Dread torching the castle fortress of Harrenhal. This can only mean one thing: he's still working on the Aegon's Conquest prequel:
— mattson tomlin (@mattsontomlin) July 14, 2025
Tomlin's Twitter account is full of vague writing updates along the lines of, "I’ve written so much this year" and "Tonight I’m going to lock in and WRITE." And then came the most exciting out yesterday:
Turning in scripts feels good 🤓
— mattson tomlin (@mattsontomlin) July 15, 2025
"Turning in scripts feels good." Does that mean he's turned in the script for Aegon's Conquest? Our interest is piqued.
The story of Aegon's Conquest is sketched out in George R.R. Martin's book Fire & Blood. Tomlin previously talked about his approach. "For me, it's about making sure that I respect George and I respect the text. And then also, it still has to be a dramatic story," he said. "Those characters have to go on a journey; they have to change; they have to go from a beginning to a middle to an end. Figuring out how to do all of that with the clues that that textbook has left for me and go, okay, I'm going to interpret this very real history and try to make it a really vivid show that hopefully people love and don't hate, doing the best I can."
Again, there's no guarantee that this particular Game of Thrones spinoff will make it to air, but out of all the ones HBO has brewing, I think it has the best chance. That said, if an Aegon's Conquest show does happen, it won't be for a while, probably not until after House of the Dragon has wrapped up.
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