One of the main characters in hit fantasy drama House of the Dragon could have been based on an empress who hid at Oxford Castle.

Based on George RR Martin's series of novels, House of the Dragon, which is set 200 years before the events of Game of Thrones, returns to TV tonight.

It tells the story of House Targaryen, focusing on Rhaenyra Targaryen's battle for the Iron Throne.

And according to historians, Oxford Castle was once home to the real-life Rhaenyra Targaryen.

An archive picture of Oxford Castle An archive picture of Oxford Castle They believe the character may have been inspired by Empress Matilda who sought refuge for three months at Oxford Castle in 1142 during a civil war known as the Anarchy.

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Matilda eventually managed to make her dramatic escape from St George’s Tower and her room in the tower at Oxford Castle can still be visited during guided tours to this day.

(Image: Oxford Castle)

Matilda eventually conceded the throne to her rival, Stephen, but her line would go on to rule.

Her grandchildren include Richard the Lionheart and King John of Robin Hood fame.

The opening episode of the epic first series House of the Dragon, which featured dragons, kings and wars, was the most watched premiere on HBO.

However, it started with a gruesome scene of a Caesarean without anaesthetic and ended with an 'abhorrent' beheading some viewers found too difficult to watch.

The second series promises to be equally bloody when it starts tonight at 9pm on Sky Atlantic.