Prior to the conquest, dancing between the alluring promises his ambitions drove, Aegon had a dream. And just as Daenys foresaw the end of Valyria, Aegon foresaw the end of the world of men coming by the hand of terrible, gelid winds as the war horse of an unknown evil dressed in darkness like those who mourn.

The Targaryen following after him hadn't forgotten his words but mistook them for another tale. And when the dragons fell dormant, Westeros disregarded it. But fate hangs in your hands.