Although Game of Thrones has ended, there are still spin-offs to come, and now a prequel TV show about the history of the Targaryens is in development alongside Blood MoonBlood Moon (the working title, although a leak suggests it may be the official title, too) wrapped filming its pilot this year and is still awaiting a full series order from HBO.

No official release date for the first spinoff has been set, but fans have been informed that Blood Moon is set thousands of years before Game of Thrones, at the end of the Age of Heroes. This week the news broke that a second prequel series is nearing a pilot order, and this one will be focusing on the history of the Targaryens as laid out in George R.R. Martin's book Fire And Blood.

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HBO is clearly keen to continue the success of Game of Thrones in a new series - and there's plenty of fan interest in Aegon the Conqueror and how the Targaryens first came to power in Westeros. Here's what we know about the Targaryen prequel TV show so far.

Game Of Thrones' Targaryen Prequel Pilot Is In Development

Fire and Blood book cover

The news broke on Sept 12th, as Deadline reported that the next Game of Thrones prequel is close to reaching a green light for a pilot. Since the original series took off, multiple spin-off series have been discussed, with no fewer than five possibilities being considered at one time. Of those five, George R.R. Martin confirmed in May that three were still moving forward, although Bryan Cogman's spin-off was not one of them. Blood Moon is the first of those three to start filming, and the other two still in development were still in the script stage. From the news this week, it seems that one of those two is about to make the leap from script stage to filming, and a few details have been leaked about what to expect. The series will be helmed by Colony co-creator/exec producer Ryan Condal, as well as (of course) Martin himself, and has been in development since last fall.

Game Of Thrones' Targaryen Prequel Story Details

Prince Aegon Targaryen flanked by members of the Golden Company - by Diego Gisbert Llorens
Prince Aegon Targaryen flanked by members of The Golden Company by Diego Gisbert Llorens

According to the same sources that claim that HBO is ready to give the series the go-ahead, the series will be "set 300 years before the events in Game of Thrones and tracks the beginning of the end for House Targaryen". The story is also said to be a "brand new take" on an idea that was originally part of Cogman's spin-off scripts. On his blog back in May, George R R Martin said that "maybe some of you should pick up a copy of Fire and Blood and come up with your own theories" when talking about the upcoming prequels.

Put all of this together, and it seems clear that this second spin-off will focus on the history of House Targaryen, as laid out in Fire and Blood. Of course, Fire and Blood is a massive book that covers hundreds of years of history, so it is unclear which particular chapter of Targaryen lore will be explored here. One of the most obvious choices would include Aegon's Conquest, which does take place approximately 300 years before Game of Thrones, but which would be difficult to spin as "the beginning of the end" for the Targaryens. Another highly likely possibility would be the Dance of Dragons, a civil war between two rival branches of House Targaryen that decimated their dragons (but which took place closer to 150 years before Game of Thrones, rather than 300).

Related: Game of Thrones: How Was The Wall REALLY Built?

Game of Thrones' Targaryen Prequel Release Date Info

Game of Thrones Season 4 Episode 8 Daenerys

No official release date has yet been set for the Targaryen prequel TV show - unsurprisingly, as the pick up has yet to be officially announced. HBO has also not commented on the reports that they are about to give this second spin-off the go-ahead. However, it's possible to speculate on a potential release date should this spin-off take the usual amount of time to go from greenlight to small screen. The first spin-off (Blood Moon) was originally announced and casting as far back as summer 2018, but didn't start filming until summer 2019, and isn't expected to be on the air until around 2021 (assuming a full season order). Should this prequel start filming in early 2020, it would then be likely to air in 2022 - which would also give the network time to assess how Blood Moon is received before deciding whether or not to order a full season. As news continues to break and HBO chimes in with the official decision on a new prequel, hopefully more will become clear about this next corner of the Game of Thrones universe.

NEXT: Oh Great, GRRM Has ANOTHER Game Of Thrones Project That Isn't Winds Of Winter