WARNING! This post contains SPOILERS for House of the Dragon's season 1 premiere.The ancestors of House of the Dragon’s Targaryens foresaw the Doom of Valyria before coming to Westeros, with such a dream connecting to Game of Thrones’ larger story. House of the Dragon season 1 is set 172 years before the birth of Daenerys Targaryen, depicting the family at the height of its dynasty, approximately one century after Aegon the Conqueror took Westeros. The Targaryens aren’t the only major family in House of the Dragon with a key link to Old Valyria, but the Doom plays a much larger role in their history than others.

One of the most important relationships in House of the Dragon is between House Targaryen and House Velaryon, both of whom descend from Valyria before the Doom. While the Velaryons fled Valyria for Driftmark long before the Targaryens, the dragonriding family had a supernatural link to the events. Before the Doom devastated Old Valyria, Daenys Targaryen had a prophetic dream that saw the events years before they occurred. As House of the Dragon episode 1’s twist ending reveals, foreseeing the Doom of Valyria wasn’t the only humanity-saving dragon dream had by the Targaryens, as Aegon the Conqueror’s Song of Ice and Fire dream compelled him to take Westeros. Seeing another terrible winter ahead that would destroy the living, Aegon dreamt that a Targaryen king or queen would need to sit on the Iron Throne to unite the realm against the Night King and White Walkers.

Related: Does Aegon Know About The White Walkers In The Books?

The Targaryens fled Valyria before the Doom happened over a century before they conquered Westeros, with House of the Dragon's main family being the only dragonlords to escape the devastation. By the time the Doom occurred, the Targaryens had resettled onto Dragonstone with their dragons in tow. However, despite having no clear idea of what caused the devastation, they weren’t spared from the details of the catastrophic Doom of Valyria. The peninsula was completely destroyed, with the Valyrian empire collapsing as a series of apparent natural disasters placed the Freehold underwater – an area known as the dreaded Smoking Sea by House of the Dragon's timeline.

What Happened During The Doom Of Valyria

Visenya, Aegon, and Rhaenys looking to the distance.
Illustration by Amok. 

After nearly five thousand years of being the thriving dominant power in Essos, the Valyrian Freehold was decimated in a single day, approximately 100 years before Aegon’s Conquest. When the Doom began, a chain of volcanoes known as the Fourteen Fires erupted, which laid all of Valyria and its surrounding lands to waste as it became consumed by ash and fire. For those who survived the volcanic eruptions, the devastation would continue as corresponding earthquakes rattled the Targaryen’s original home. Valyria itself broke apart and caused the ocean to sweep in and place much of the area under the sea. During the times of Game of Thrones and House of the Dragon’s characters, the water-covered Valyrian Peninsula is known as the Smoking Sea, which sailors fervently avoid in fear of the location being haunted by demons.

What Really Caused The Doom Of Valyria?

GOT's Daenerys Targaryen and HOTD's Daemon Targaryen

The true cause of the Doom of Valyria is unknown in House of the Dragon. While descendants of Valyria and historians have theorized the Doom to be a result of natural disasters, others speculate that sorcery by the Valyrians was the cause. This theory is seemingly supported by King Viserys I Targaryen in House of the Dragon, as he tells Rhaenyra that the dragons had influenced the devastation of the area. Considering the Doom killed all living dragons but those that House Targaryen's family members had already fled with, the disaster may have been a way to try to rid the world of the creatures.

How The Targaryens Escaped Before The Doom Of Valyria

Milly Alcock as Rhaenyra Targaryen in House of the Dragon with Emilia Clarke as Daenerys Targaryen in Game of Thrones

As House of the Dragon’s King Viserys mentions to his daughter Rhaenyra, their ancestor Daenys Targaryen had a strong prophetic dream about the Doom 12 years before it occurred. She told her father, Aenar, who listened to the dream and decided to move the Targaryens and their belongings – including five dragons – to Dragonstone in Westeros in 114 BC. When the Doom of Valyria came 12 years later, the dragonriding family was already firmly established at Dragonstone, leading them to be the only dragonlords to survive the catastrophe.

Related: Daemon's Dark Sister Sword Has A Secret Bran Stark Connection

What Happened To Valyria After The Doom

Map of Westeros and Essos from "Game of Thrones"

After the Doom, Valyria lost all of its records and became the Smoking Sea, but its history is still taught by House of the Dragon's Targaryens on the Iron Throne. Valyria’s fall would lead to the Century of Blood in Essos, which was marked by the Volantenes trying to rebuild the empire under their own rule. Rather than a structured war, the Century of Blood was a period of anarchy in which the surviving peoples and areas of Essos tried to retake the empire for themselves, leading to the formation of the Free Cities.

Volantis attempted to conquer the rest of the colonies but failed when the ancient Game of Thrones colonies banded together against the Volantenes. Eventually, Aegon I Targaryen entered the conflict on the side of Volantis’ enemies, and with three dragons at his side, attempts to make the Free Cities a new Valyrian empire were thwarted. Following the Doom of Valyria and Century of Blood, Essos’ political landscape largely reflected that which is depicted in House of the Dragon and Game of Thrones through Daenerys' story.

New episode of House of the Dragon release Sundays on HBO.