The season 3 finale of House of the Dragon has seemingly altered the understanding of a pivotal prophecy that bridges the gap between the prequel and its predecessor, Game of Thrones. In a dramatic moment, Rhaenyra Targaryen declares herself "The Prince That Was Promised" to her soldiers, a declaration that, according to analysis, could have significantly expanded the prophecy's reach beyond the Targaryen lineage.
Historically, the concept of The Prince That Was Promised was a secret passed down through Targaryen kings, originating from Aegon the Conqueror. He foresaw a dire threat from the White Walkers and entrusted this knowledge to his bloodline. While a similar myth, Azor Ahai, exists in Essos, and some maesters may have encountered related texts, the prophecy remained largely confined to the Targaryen family in Westeros.
Rhaenyra's public proclamation to her army, however, implies that this closely guarded secret is now out. While her soldiers may not have understood the prophecy's full significance or context, the mere dissemination of the phrase could have seeded its legend throughout Westeros. Over the two centuries separating House of the Dragon from Game of Thrones, the prophecy could have evolved from a Targaryen family concern to a more widely discussed, albeit still obscure, concept.
This shift from a private Targaryen secret to a potentially broader legend could explain why the prophecy is occasionally mentioned among characters in Game of Thrones, even if it wasn't common knowledge among the general populace. Coupled with the growing fear of threats beyond the Wall, the prophecy might have become a symbol of hope for a prophesied savior. This single scene, therefore, could retroactively alter the audience's perception of how integral the prophecy was to the broader narrative of Westeros, potentially setting in motion the chain of events that leads to the story told in Game of Thrones.