In Episode 4, Viserys shows Rhaenyra a dagger with words inlaid upon it that read, “From my blood come the prince that was promised, and his will be the song of ice and fire.” This references back to the show's first episode, when Viserys tells her that Aegon the Conqueror predicted a long winter that only Targaryens could fight — which he referred to as the "Song of Ice and Fire."