Aegon’s dream
We knew Westerosi history would tie House of the Dragon to Game of Thrones; the prequel begins by reminding us that all this is taking place nearly 200 years before our pal Daenerys Targaryen was born. But there’s also some mythology at work here, blended with a bit of retcon. When Viserys is about to name Rhaenyra his heir, he shares with her a secret passed down through generations of Targaryens from the first Lord of the Seven Kingdoms, Aegon the Conquerer. It’s a prophetic dream Aegon had envisioning the rise of the White Walkers that we see in Game of Thrones—and his belief that Westeros will need to be united behind a Targaryen ruler (you know, that old Song of Ice and Fire) to survive the threat.
