Daenerys Stormborn brought fire and blood back to Westeros. But for many years that was all the Seven Kingdoms knew. Her ancestors once ruled the Realm with the power of fire made flesh. That includes during the peak of House Targaryen’s power, the era House of the Dragon will explore. When exactly was that, though? And what other families wielded played major roles during that deadly civil war? This is where the House of the Dragon prequel series fits into Game of Thronestimeline.

Milly Alcott as Princess Rhaenyra Targaryen in House of the Dragon.
HBO

When Does House of the Dragon Take Place Compared to Game of Thrones?

Westeros’s history dates back millennia, but the calendar adopted under Targaryen rule covers a relatively small period of time in Game of Thrones’ history. It’s based on the end of Aegon’s Conquest. Two years after he arrived in Westeros—on what became King’s Landing—the High Septon of Oldtown crowned Aegon king. From that point forward, the Seven Kindgoms used a new calendar, with “AC” representing “After Conquest” and “BAC” representing “Before Conquest.”

Game of Thrones began nearly three centuries after Aegon’s formal ascension in 298 AC. The show generally covered one calendar year per season, but that timeline changed towards the end. Ultimately Game of Thrones spanned roughly seven years total.

House of the Dragon will cover a longer period of time overall but a much shorter time during its primary event. Here’s more about the timeline we’ll see in House of the Dragon.

It all begins with the Old King, Jaeherys I, in 103 AC. ( An official image confirmed we’ll see Jaeherys.) The longest-ruling Targaryen king had no obvious heir. His grandson Viserys ascended to the throne after a Great Council named him heir shortly before his grandfather died.

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Viserys I wanted to avoid questions about royal succession following his own death. So in 105 AC, the King made the Lords of Westeros swear to accept his daughter Rhaenyra as Princess of Dragonstone and his heir. Viserys chose her following his wife’s death during childbirth. He had no surviving sons, and Rhaenrya was set to become the first woman to rule Westeros. That was not without controversy, however. Viserys placed her ahead of his presumed successor, his brother Daemon.

But the real trouble started a year later. Viserys married Alicent Hightower, and they had a son, Aegon. Queen Alicent wanted her child to inherit the Iron Throne over his older half-sister.

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Despite the King’s efforts to keep the peace, and his insistence Rhaenrya remained his heir, during Viserys’ reign Rhaenyra and her supporters clashed with Alicent and hers. A cold war (that saw plenty of violence) became a civil war of fire and blood following the death of King Viserys in 129 AC. The Dance of the Dragons lasted two deadly years, ending in 131 AC. All of which means House of the Dragon is set roughly 200 to 170 years before Game of Thrones begins.

Which Game of Thrones Families Will Appear on House of the Dragon?

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The most famous houses seen on Game of Thrones—Stark, Baratheon, Lannister, Arryn, Tully, Greyjoy, Tarly—played roles during the Dance of the Dragons. Each swore to accept and support Rhaenyra as Viserys’ heir. But while some fulfilled their oath following his death, others fought for Aegon’s claim. (Some because they believed a son must come before a daughter in the line of succession.)

We won’t tell you which stayed true to their oath. It’ll be more fun to see who joined the “Blacks” (Rhaenyra) and who joined the “Greens” (Alicent/Aegon). We will tell you none of Game of Thrones‘ most famous families played the biggest roles during the events that feature in the timeline featured in House of the Dragon.

What New Families Will Play Major Roles on House of the Dragon?

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House Velaryon and House Hightower might be unknown to many Game of Thrones viewers, but that won’t be the case soon. Each powerful and influential family played significant parts during the timeline of the Targaryen civil war we’ll see play out in House of the Dragon.

The ancient House Hightower is one of the Realm’s most important and powerful families. Believed to have descended from the First Men, their ancestral seat, the Hightower, looms over the great port city of Oldtown, home of the maesters’ Citadel. The Hightowers are one of the Seven Kingdom’s oldest, wealthiest, and most respected Houses. And outside of the Targaryens, no one played a bigger role in bringing war to Westeros. Ser Otto Hightower served as Hand of the King to three Targaryens, including Jaeherys I and Viserys I. He was also a hated rival of Daemon Targaryen. And he arranged the marriage of his daughter Alicent to the widowed King, a union that nearly led to the destruction of House Targaryen.

Like the Targaryens to whom they swore allegiance, the ancient House Velaryon of the island Driftmark were descendants of Old Valyria. (Hence their blonde hair.) They arrived in Westeros before Aegon’s family, but their time in the Realm is relatively short compared to other great houses. And despite their blood and ancestry, instead of riding dragons, Velaryons mastered the seas. They were some of the finest in the world, frequently serving Targaryen small councils as master of ships.

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House Velaryon was House Targaryen’s oldest and most trusted ally. The two families also strengthened their bond with marriages. Of course, not all marriages are happy. And sometimes they help lead to war.

House of the Dragon will reveal its timeline and new conflicts when it premieres on HBO August 21.