HBO is returning to Westeros!

The network that made history with Game of Thrones and experienced comparatively moderate success with the spinoff House of the Dragon is now developing a third series based in the medieval fantasy world of author George R.R. Martin.

The Hollywood Reporter revealed this week that HBO has greenlit a project with the reported working title of Aegon's Conquest.

The story of the first Aegon Targaryen will be familiar to diehard GoT fans.

(Although those who watched the first two series more casually can be forgiven if that name no longer rings a bell. There's an awful lot of lore in this franchise!)

Basically, Aegon I is the guy who began the process of uniting the Seven Kingdoms when he made a dragon-back flight from Old Valyria with his sister-wives Rhaenys and Viseyna.

Aptly known as Aegon the Conqueror, this founder of the Targaryen dynasty is frequently name-dropped by other characters, particularly his descendants on House of the Dragon.

History-obsessed King Viserys I Targaryen (Paddy Considine) was especially interested in the life and achievements of the OG Aegon, and with good reason.

The shadow Aegon and his three dragons still loomed large during Viserys' reign, and the troubled king was succeeded on the Iron Throne by his first son, Aegon II (who was then succeeded by his nephew Aegon III).

That's one reason why some fans are surprised by this week's news.

After all, the exploits of Aegon have already been discussed and dissected on House of the Dragon.

It's easy to see why some viewers might feel that that particular topic has been covered sufficiently.

But it's worth noting that the Game of Thrones franchise has been dividing its fan base since the day the pilot episode debuted in 2011.

While there may have been some universal letdowns along the way (five years later, the Game of Thrones series finale has found few revisionist defenders), HBO deserves a world of credit for taking a risk on two unproven showrunners and their plan to develop an unfinished series of fantasy novels.

And even in today's risk-averse television landscape, when it comes to the world of GoT, HBO execs remain committed to shelling out for top talent and allowing showrunners plenty of freedom.

For the as-yet (officially) untitled Aegon series, the network is bringing in Mattson Tomlin, a buzzed-about writer who collaborated with director Matt Reeves on 2022's The Batman, as well as the upcoming sequel The Batman Part II.

Tomlin is currently the showrunner for Netflix's Terminator: The Anime Series.

So the guy is no stranger to the sort of genre fare that serves as a breeding ground for obsessive fandom.

George R.R. Martin adaptations have delivered the closest thing to reliability that HBO has seen in recent years.

Ratings for House of the Dragon paled in comparison to those for Game of Thrones (the GoT finale brought in 19 million viewers, while Dragon received a comparatively paltry 2.7 million).

But the latter series was still the network's biggest hit of the past two years by a considerable margin.

So it's not hard to see why HBO would be all-in on Westeros.

However, there are concerns that fans might soon experience dragon fatigue.

After all, in addition to Dragon and Aegon, HBO is currently developing A Knight of the Seven Kingdoms: The Hedge Knight, which will center on Ser Duncan the Tall and his squire, Egg.

The series will be set about 50 years before the events of the original Game of Thrones.

There's plenty of source material there, as Martin has already penned three novellas in that series.

But as with A Song of Ice and Fire -- which served as the inspiration for GoT -- the author has yet to complete the saga.

Here's hoping the showrunners of the current and upcoming Martin adaptations won't have quite as much trouble as their predecessors when it comes to nailing the dismount!

Tyler Johnson is an Associate Editor for TV Fanatic and the other Mediavine O&O sites. In his spare time, he enjoys reading, cooking, and, of course, watching TV. You can Follow him on X and email him here at TV Fanatic.