"House of the Dragon"'s Long Night Prophecy Twist Came Right From George R.R. Martin

"House of the Dragon" just added a major piece to "Game of Thrones" lore. At the end of episode one, King Viserys (Paddy Considine) officially names his daughter, Rhaenyra (Milly Alcock), as his heir. She would be the first queen in the history of Westeros. He also apologizes to her for being obsessed with having a son instead of valuing her and training her for this moment.

Then, Viserys shares with her key information about Aegon the Conqueror, the first Targaryen king who united the seven kingdoms of Westeros under his rule. He tells her that Aegon dreamed of what "Games of Thrones" fans know as the Long Night, culminating in the Battle of Winterfell. Here's what he says:

"Ambition alone is not what drove him to conquest. It was a dream. And just as Daenys foresaw the end of Valyria, Aegon foresaw the end of the world of men. It is to begin with a terrible winter, gusting out of the North. Aegon saw absolute darkness riding on those winds, and whatever dwells within will destroy the realm of the living. When this great winter comes, Rhaenyra, all of Westeros must stand against it. And if the world of men is to survive, a Targaryen must be seated on the Iron Throne. A king or queen, strong enough to unite the realm against the cold and the dark. Aegon called his dream the song of ice and fire. This secret has been passed from king to heir since Aegon's time. Now you must promise to carry it and protect it."

During his speech, Viserys also gestures to a Valyrian steel dagger on his belt — the same one Arya, hundreds of years later, uses to kill the Night King. The cast and showrunners of "House of the Dragon" share with POPSUGAR the significance of the prophecy and where the idea came from to include it in the show.

A Song of Ice and Fire is the name of the book series "Game of Thrones" is based on. Aegon's dream isn't mentioned in "Game of Thrones" or George R.R. Martin's books, but it was Martin's idea. Co-showrunner Ryan Condal tells POPSUGAR, "That was the detail that George actually gave us early in the story break, the idea that Aegon the Conqueror was himself a dreamer, and that's what motivated the conquest, which [George] mentioned casually in conversation, as he often does, with huge pieces of information like that."

"It really changed a lot our thinking of the way we saw the Targaryen reign and what it was all about," Condal says. "[Aegon] pursued the conquest thinking that this was an imminent problem. We have the dramatic irony . . . that it takes quite some time for this prophecy to come true."

The idea of passing down the dream and its prophecy from king to heir came from the showrunners. "The way that we took George's idea and spun it dramatically for 'House of the Dragon' was this idea that, at some point in Aegon's life as he got older and matured, he must have realized that one day the White Walkers weren't coming for dinner during his lifetime," Condal says. "And then we decided that . . . [if] he believed in this enough to conquer Westeros, he surely would've believed in it enough to pass the idea on. So we had this become the legacy that the Targaryens have, and they pass it from king to heir as . . . a reminder that the Iron Throne is a privilege and it's a duty and a responsibility, and you have to . . . improve the kingdom and make it stronger and more united and not use it as a pursuit for selfish gain. And we'll see how that hangs on as our story develops."

Considine tells POPSUGAR that Viserys is "a bit of a dreamer, and he does believe in prophecies." He explains that this is a big reason he thinks Rhaenyra should be heir. "Viserys is very much like, 'Who can I entrust with this prophecy? I can't entrust Daemon with it. I can't entrust Otto Hightower with it, or anybody,'" he says.

Alcock says, "Reading that scene, ultimately for me, was about how [Rhaenyra] was finally seen by her father. And I think that's what she wants. She doesn't want to sit on the throne. She wants change. And if the throne is used as an agency for change, then she's going to take it by the balls."

Emma D'Arcy, who plays the older Rhaenrya, reflects on how the "huge moment" stays with her for the rest of her life. "Receiving that from her father is something akin to feeling chosen and feeling seen by him," they explain. "It attaches her to the legacy of her family and of a ruling family, and that for Rhaenyra is completely bound up in her individual identity."

The show doesn't go into detail about where exactly the Valyrian steel dagger came from, but presumably it's a Targaryen family artifact from before the family fled Valyria. Whether Aegon saw specifically that the dagger would be the way the darkness ended is unclear.

Considine tells POPSUGAR how he played Viserys's connection to it. He says, "The knife was a real sacred object to me. Viserys wears it at all times, and even when I'm not wearing it, it's never more than a few feet away from me. It's a very important artifact for him."

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