HBO has ordered a "Game of Thrones" prequel to series called "House of the Dragon."The show will be at least 10-episodes long and is based on George R.R. Martin's "Fire and Blood" book."Fire and Blood" begins about 300 years before the events of "Game of Thrones," and is written from the perspective of a maester who is detailing the history of House Targaryen.HBO programming president told Variety his "guess is we'll see it on the air in ."Keep reading for everything we know about the series so far.Visit Insider's homepage for more stories.In the same day we learned one "Game of Thrones" prequel idea (this one about the Long Night) was reportedly dead at HBO, the company announced a series order for "House of the Dragon"a different prequel all about the history of House Targaryen.Keep reading for a dive into everything we know about the new "Game of Thrones" spinoff series.'House of the Dragon' is based on yet another unfinished book series from George R.R. Martinbut this one is differentIn 2018, Martin published the first of two planned volumes in a series called "Fire and Blood," which detail the history of House Targaryen starting with Aegon's Conquest in Westeros.Unlike his unfinished "A Song of Ice and Fire" series, these books are not a narrative story told from the point-of-view of various protagonist characters. Instead, "Fire and Blood" reads more like a history book. It's all written as if from the perspective of maestersthe historians and scholars in the Citadel of Westeros.That means the events and characters described are more generalized, while also told in a narrative way and from a biased source.It also means that it doesn't really matter that Martin hasn't yet published "volume two" in the series."Fire and Blood" is an expansion on the Targaryen history Martin had already outlined in his encyclopedic book titled "A World of Ice and Fire: The Untold History of Westeros and the Game of Thrones" (coauthored by Linda Antonsson and Elio Garcia).While "Fire and Blood" expands on these stories and adds more details and characters, it's not an incomplete narrative in the way "A Song of Ice and Fire" currently is, thanks to the outlined history we already have in "A World of Ice and Fire."The new series doesn't run the risk of overtaking Martin's work in a way that would be detrimental to its storytelling in the way "Game of Thrones" surpassing "A Song of Ice and Fire" ultimately was.Martin has not yet announced a planned publish date for either "Fire and Blood: Volume Two," or the sixth book in his "A Song of Ice and Fire" series, "The Winds of Winter." He has said in recent interviews that his primary focus is "The Winds of Winter," and then back to "Fire and Blood."There is more than enough material in 'Fire and Blood' for multiple seasons, but right now HBO has only announced 10 episodesSince it's extremely early in the process, HBO has not yet indicated the overall structure plan for "House of the Dragon." All we know is there will be at least 10 episodes made, which was the number of installments in a standard season of "Game of Thrones.""Fire and Blood" starts with Aegon Targaryen's Conquest, an event alluded to throughout "Game of Thrones." This was the war in whichAegon I, along with his sister-wives Visenya and Rhaenys, came to Westeros and brought six of the seven kingdoms under his rule through war and diplomacy.Aegon's dragon was called Balerion the Black Dread, and is said to be the largest dragon ever seen in Westeros. His sisters each had their own dragons, Vhagar and Meraxes.Since dragons are an essential part of every aspect in Targaryen history, you can bet on seeing them on the "House of the Dragon" prequel series.Don't expect familiar faces on the show, though. "Fire and Blood" begins 300 years before the events of "Game of Thrones," which means none of the characters you already know from the HBO series will be present. Instead you'll hear familiar House names like Stark, Baratheon, and Lannisterall of the ancestors of your favorite characters who played a part in the rise of House Targaryen.By moving forward with a series based on Martin's published works, HBO is getting back to the formula that helped make the early seasons of "Game of Thrones" such a resounding success. The Long Night prequel idea had very little to go on in terms of Martin's published histories and dramas involving the lords and ladies of Westeros.There were only ever a few sentences about what happened in the Long Night and Age of Heroes, and what led to the White Walkers' first attack on Westeros.Now, with "Fire and Blood," the creators have a clear road map to follow with the history of House Targaryen and simultaneously enough wiggle room to flesh out the characters and dialogue in their own way.'House of the Dragon' will be helmed by Miguel Sapochnik and Ryan Condal, with Sapochnik also serving as director on some episodesMiguel Sapochnik is a director who rose to prominence after his first two "Game of Thrones" episodes, "The Gift" and "Hardhome," premiered in 2015. "Hardhome" centered on Jon Snow's first confrontation with the Night King and the massacre of wildlings in a fortress beyond the Wall, and was handily the best episode of that season (and some would argue among the best of the whole series).Sapochnik returned to direct season six's back-to-back stunners "Battle of the Bastards" and "The Winds of Winter," in which Jon Snow and Sansa won back Winterfell from Ramsay Bolton and then Cersei blew up the Sept of Baelor.He didn't direct any season seven episodes (during that time he helmed the pilot episode of Netflix's "Altered Carbon"), and then returned for "Game of Thrones" season eight's "The Long Night" and "The Bells"the two most action-packed installments of the final season."House of the Dragon" is the first series Saponchik will serve as showrunner on, and is the first project that is part of his "overall deal where he will develop and produce content for both HBO and HBO Max," according to the press release.He'll direct the pilot episode of "House of the Dragon," and then an unconfirmed number of "additional episodes."Sapochnik's coshowrunner Ryan Condal will be the lead writer for the whole series.Condal was the cocreator and showrunner of a sci-fi series called "Colony," which ran on USA for three seasons. He was the writer of MGM's "Hercules" and is currently adapting the graphic novel Analog as a feature for Lionsgate.George R.R. Martin and "Game of Thrones" producer Vince Gerardis are also listed as executive producers.No additional directors or cast have been announced yet, though there is a team of writers working on the showThere isn't any news yet on who else will be directing episodes with Sapochnik, andno cast announcements have been made, either.But there are three people who are writing the series alongside showrunner Ryan Condol."Colony" writer and executive producer Wes Tooke is one of the people helping shape "House of the Dragon" in the writer's room. Then there's Claire Kiechel, whose recent work on Netflix's "The OA" and HBO's "Watchmen" was nominated for the 2020 Writers Guild Awards. Lastly Ti Mikkel, who worked as writer's assistant at Martin's Fevre River Packet Company, is also on the writing team this new prequel series.The other prequel, which is reportedly not moving forward, had Jane Goldman on board as showrunner and a woman director for its pilot, along with a diverse cast. Many people are hoping "House of the Dragon" similarly breaks away from the mold set by "Game of Thrones," in which the writers room, director's chair, and lead cast over eight seasons was occupied by primarily white men and women.Another announcement some fans might be on the lookout for will be the creative teams behind-the-scenes.Will Ramin Djawadi bring a new take on his iconic "Game of Thrones" score to this series' Could lead phenomenal lead costume designer Michele Clapton return to the HBO family for "House of the Dragon"' Will sound designer Paula Fairfield once again be the one making dragons come to life'All this and more is still just speculation.No planned premiere date has been announced, but HBO has said 2022 is likelyThis is to be expected so early on in the process. Between preproduction, filming, and postproduction (especially involving all those dragons), fans probably shouldn't expect to see "House of the Dragon" on HBO until 2022."They are in the room breaking story right now," HBO programming president Casey Bloys told Variety. "My guess is we'll see it on the air in ."We'll update this article as more information about "House of the Dragon" is revealed. In the meantime, you can ready yourself for the new series by reading Martin's first "Fire and Blood" book.Read more:31 questions the 'Game of Thrones' series finale left unansweredThe 'Game of Thrones' script reveals what was going through Dany's head before she chose to burn down King's LandingHow 'Game of Thrones' nearly ended before it began thanks to a disastrous pilot23 details uncovered in the 'Game of Thrones' season 8 episode scriptsJoin the conversation about this storyNOW WATCH: Each year, the US gets around 4 times as many twisters as the rest of the world combined ' here's why Click here to read full news..