The White Walkers were the threat from the North dreamed about by the first king to sit on the Iron Throne, Aegon the Conqueror (Aegon I Targaryen). With the dream came the prophecy about the Prince Who Was Promised, and together these two things were passed down from Targaryen king to Targaryen king. Viserys I would eventually go on to share the burden of the secret that came along with the crown and the Iron Throne, with his daughter Rhaenyra. But what about Aegon II Targaryen?
Viserys was adamant throughout his reign that the person who would succeed him after his death and claim the Iron Throne would be his daughter, Rhaenyra, so, after declaring her as his heir, he revealed to her the secret that the leaders of House Targaryen had been burdened with: a prophecy engraved into a dagger speaking of a prince who would unite the realm.
Unfortunately, Rhaenyra would be the last Targaryen to ever hear the prophecy. Because of her unexpected death near the end of the Dance of the Dragons, she was never able to share the prophecy with any of her children, and so the true burden of the Iron Throne would die with her.
While on his death bed, when he was completely drugged up by milk of the poppy, Viserys began to mutter and mumble about the prophecy, and the Prince That Was Promised to who he assumed was Rhaenyra, answering a question she had asked previously.
Unfortunately for the king, he was actually talking to Alicent, who had no context for what he was talking about, and upon hearing the very disjointed rendition of the prophecy, she assumed he was talking to her about their son Aegon II Targaryen, rather than the Targaryen ancestor.
In one final effort to proclaim Aegon as the rightful heir to the throne and secure her son’s position as king, Alicent left the room in his haste to tell the court a misinterpreted version of the dying, delirious king’s last words.
In truth, the thought that Aegon II Targaryen would succeed him one day had never once crossed Viserys’ mind, evident by the fact that in all his years as king he’d never shared the prophecy with him. Aegon didn’t even want to be king, claiming on multiple occasions that he was unfit for the crown (his brother Aemond was quick to agree with him).
It’s safe to assume that based on everything, Aegon II Targaryen had no clue about the threat of the White Walker and therefore never truly understood the importance of taking over House Targaryen and making sure that a Targaryen descendant would remain on the throne. All he really knew was that his mother wanted him on the throne, so that’s where he would be, no matter how much he didn’t feel like he was right for it.
Did Aegon I Targaryen Know About the White Walkers?
Aegon the Conqueror (Aegon I Targaryen) was the ancestor to Rhaenyra and Daenerys Targaryen. In the first episode of House of the Dragon, Rhaenyra’s father reveals to her a family secret that has been passed down from heir to heir concerning the fate of Westeros: “Aegon saw absolute darkness riding on those winds, and whatever dwells within will destroy the world 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, then 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.”
The Threat from the North
Aegon I Targaryen spent his years aboard his beast of a dragon, Balerion, conquering all of Westeros and making sure that the 7 kingdoms were united under one flag so that, when the threat from the North did eventually arrive along with the Longest Winter, House Targaryen would be prepared to take it head on along with the support of all the kingdoms combined.
Fans of Game of Thrones already know that the threat from the North was the army of White Walkers led by the Night King and this was eventually taken care of through the combined efforts of the alliance between the living armies (including those led by the Arryns, Baratheons, Starks, and Targaryens).
Arya Stark even uses the catspaw dagger (which had the inscription of the prophecy engraved into it) to kill the Night King.
Why was No One Aware of the Prophecy in Game of Thrones?
One would think that such an important prophecy would survive and feature quite prominently during the events of Game of Thrones, especially since the threat of the White Walkers arrives during their lifetime, so why does it seem like it wasn’t shared further than Rhaenyra in House of the Dragon?
It seems that, unfortunately, Rhaenyra was the last heir to ever hear about the prophecy of the Prince That Was Promised before House Targaryen broke into a civil war. Her unexpected and brutal death near the end of the war was more than likely the reason she was never able to officially pass the secret of the prophecy on to any of her children.
The unfortunate loss of it to the bloodshed of war led to the people of Westeros believing that the Night King and his White Walkers were nothing more than stories that were made up by parents to get their children to listen to them and they would come to pay for it.
It is hinted that Daenerys’ older brother, Rhaegar, learned about the prophecy before his death and shared it with his wife, which Daenerys sees in the visions she is shown as the House of the Undying, but she never actually learns about the prophecy.