The battles, backstabbing and bloodshed between the houses of noble families was at the heart of the Game of Thrones story.

Simmering rivalries, old wounds and the deadly battle for control raged between powerful families, as the battle for the Iron Throne ripped through the Seven Kingdoms.

House Targaryen, House Hightower and House Velaryron rule in House of the Dragon – but who are they and how do they fit into the Game of Thrones universe?

At the start of House of the Dragon, House Targaryen are the most powerful force in Westeros with their dragons and King Viserys reigning supreme.

However, they aren’t the only powerful House in Westeros when this medieval fantasy epic begins…

“Every time a new Targaryen is born, the gods toss the coin in the air and the world holds its breath to see how it will land." George R.R. Martin, A Storm of Swords.

The first royal house of the Seven Kingdoms, the Targaryen’s took control after Aegon’s conquest and his reign launched the King’s Guard, Small Council and Iron Throne – which would go to be features way beyond his lifetime.

After Aegon, Targaryen rulers included Maegor the Cruel, Jaehaerys and then House of the Dragon picks up with King Viserys.

The appointment of Viserys, the grandson of King Jaehaerys, established the rule that power can’t be passed down to a woman – which is a significant stumbling block for Viserys at the start of House of the Dragon as he looks for an heir.

House of the Dragon will follow the story of House Targaryen from the height of its powers under Viserys to the embers and ruins that we saw Daenerys rise from at the start of Game of Thrones.

When House of the Dragon commences, Viserys rules as the King of Westeros, having been chosen by a Great Council to succeed his grandfather, Jaehaerys.

After the loss of his wife, Aemma Arryn, and their infant son, Baelon, Viserys goes against tradition and designates his daughter, Rhaenyra, as his heir, side-lining his brother, Daemon Targaryen, in the succession.

Later, Viserys marries Alicent Hightower, resulting in the birth of a son, Aegon. This decision triggers a succession crisis, igniting the inaugural Targaryen civil conflict, famously dubbed the Dance of the Dragons.

House Hightower weren’t a prominent force in the original Game of Thrones series but are at the height of their powers at the beginning of House of the Dragon.

Based in Oldtown, the powerful and noble house have the motto, ‘We Light the Way’. They are known to dabble in black magic and alchemy and are among the oldest of the Houses in Westeros.

At the start of House of the Dragon, Otto Hightower is the longstanding Hand of the King. And his daughter Alicent is close friends with King Viserys daughter, Princess Rhaenyra.

Otto encourages Alicent to get close to the king after the death of his wife Aemma, leading to Alicent and Viserys’ marriage and their son Aegon, who Otto convinces her to fight for as heir to the Iron Throne.

Otto is dismissed by the King once he catches onto all of his behind the scenes scheming.

House Velaryon is one of the oldest and wealthiest houses in Westeros, with a Valyrian bloodline as ancient as House Targaryen. The rulers of Driftmark are close and old allies to House Targaryen and sworn to Dragonstone.

They came to Westeros before the Targaryens and helped in Aegon’s conquest of the Seven Kingdoms, ruling the seas and Blackwater Bay while the dragon-riding Targaryens dominated the skies.

At the start of House of the Dragon, Corlys Velaryon rules the House. Known as the Sea Snake, Corlys is a self-made man for fortune, who earned great riches at sea. He served as Viserys’ Master of Ships and commands the Royal Fleet.

He is married to The Queen ‘Who Never Was’, Rhaenys Targaryen, who was overlooked as ruler of Westeros for King Viserys. They have two children. Laena and Lenor. Laenor is the rider of the Targaryen dragon, Seasmoke.

Following Viserys’ refusal to wed the 12-year-old Laena and instead choosing Alicent Hightower, Corlys resigns from his position on the King's Council and throws his support behind Daemon Targaryen in the conflict against the Triarchy.

Subsequently, after the war concludes, Viserys opts to unite Rhaenyra with Laenor in marriage, aiming to forge a political bond with House Velaryon.

In House of the Dragon, the formidable Lannister house, ruling the Westerlands from Casterly Rock, plays a pivotal role in the civil strife, with Tyland assuming the role of Master of Ships and his twin brother, Jason as Lord of Casterly Rock.

Despite Jason’s unsuccessful attempt to court Rhaenyra during a royal hunt, the Lannisters, known for their golden hair and reputation for always paying their debts, remain a powerful force intertwined with the politics of Westeros both past and present.

House Strong, led by Lord Lyonel Strong, serves as a significant power in House of the Dragon, with Lyonel rising from Master of Laws to Viserys' Hand. Harrenhal, their seat, is steeped in a cursed history, and despite their ambitions, the Strongs face an uncertain future.

Cunning and scheming, Larys Strong has risen to become Queen Alicent's closest confidant, skilfully guiding her to uncover Princess Rhaenyra’s clandestine affair with Ser Criston Cole. Larys further cemented his influence by orchestrating the demise of his own father and brother, a calculated move prompted by Queen Alicent’s desire for her father to return to King’s Landing.

Ser Harwin was Princess Rhaenyra Targaryen’s secret lover and fathered her three children, despite her marriage to Prince Laenor Velaryon. Rumours of their affair circulated within the Red Keep, prompting Ser Harwin and his father to retreat to Harrenhal. Tragically, both perished in the fire orchestrated by Larys before Ser Harwin could officially take up his role as Lord of Harrenhal.

Although not as prominently showcased as in Game of Thrones, House Baratheon maintains significance within the narrative. Towards the conclusion of the initial season, we witnessed Boros Baratheon, Lord of Storm's End, decline Prince Lucerys Velaryon's proposal and align with the Greens (the faction in support of Queen Alicent’s son, Prince Aegon, as heir to the Iron Throne). Presently allied with House Targaryen’s Greens, Boros is poised to assume a more substantial role in the forthcoming season of the series.