What the 'A Song of Ice and Fire' Reference in 'House of the Dragon' Means

George R. R. Martin's vast, fascinating world of the Seven Kingdoms has a long history, all of which is influenced by one important prophecy: The Song of Ice and Fire.

House of the Dragon references this key moment in the history of Martin's books in its premiere episode, though it also makes a subtle change to how events were depicted in HBO's flagship show.

What the 'A Song of Ice and Fire' Reference in 'House of the Dragon' Means

In the premiere episode, King Viserys I (Paddy Considine) tells his daughter Rhaenyra (Milly Alcock) that he has decided he wants her to be his heir, and has chosen her over his brother Daemon (Matt Smith) to take the Iron Throne.

Upon telling her that he wants her to rule after his death, King Viserys I informs her of a prophecy that has been passed down from ruler to heir for generations since the days of Aegon the Conqueror.

He explains that the first Targaryen ruler of Westeros had a prophetic dream known as the Song of Ice and Fire, in which he foresaw the end of men would begin with a long winter that would bring with it a dark and foreboding enemy.

This enemy, fans of Game of Thrones will know, is the Night King and his White Walkers. King Viserys I tells Rhaenyra that the world of men must stand against this enemy if they have any hope of defeating it, but that a Targaryen must be on the Iron Throne to ensure this is the case.

This changes the way fans may understand Game of Thrones, or at least how they may now expect events in Martin's books to unfold in comparison to the HBO series.

In the HBO series the Kingdoms did unite against the Night King and the White Walkers, and they did defeat the enemy, but it was not a Targaryen on the Iron Throne at the time, it was Cersei Lannister (Lena Headey).

In fact, Cersei refused to help in the war against the Night King, and Daenerys Targaryen (Emilia Clarke) and Jon Snow (Kit Harington) led the battle without any input from the Crown.

In the end, after defeating the Night King, Daenerys took the Iron Throne by force, but before she could sit upon it she was killed, undermining the prophecy set out in House of the Dragon.

However, while this is how the story took place in the show, it is not necessarily how events in the books will take place, particularly because the last few seasons of Game of Thrones went beyond Martin's series.

Martin has said that his books will end differently to the show, and his close involvement with House of the Dragon suggests that the reference to the Song of Ice and Fire is important.

It could mean that Daenerys will take the Iron Throne to save the realm, or perhaps that the Targaryen Prince That Was Promised will do so instead. It was revealed in the HBO show that this prince was none other than Jon Snow, aka Aegon Targaryen.

When Jon Snow learns of his true heritage in the HBO show he refuses to become ruler of Westeros, and following Daenerys' death he is sent to the Night's Watch and chooses to go beyond The Wall.

There are two books in Martin's franchise left to be released, so things could turn out very differently for both these characters, particularly given the reference made in House of the Dragon.

House of the Dragon airs Sundays at 9 p.m. ET on HBO and HBO Max.