Versailles: What is the true story of the Man in the Iron Mask?

But what is the truth behind this storyline? Here's what we know.

Who was 'The Man in the Iron Mask' – and did he really exist?

"The Man in the Iron Mask" is the name given to an unidentified prisoner arrested during the reign of French king Louis XIV and held in prison until his death. His identity was unknown – because, you guessed it, he was forced to wear a mask that completely obscured his face.

The masked man was said to be kept in the custody of a jailer and former musketeer named Bénigne Dauvergne de Saint-Mars, for the whole 34 years of his imprisonment.

Together they moved between a number of prisons including the Bastille and the Fortress of Pignerol, until he died under the name of "Marchioly" on 19th November 1703. Louis XIV died in 1715.

There were rumours about this mysterious masked prisoner during his lifetime, and many written records do declare his existence. A Bastille official wrote in his memoirs about the arrival of his new boss (Saint-Mars) alongside a man "who is always masked and whose name is never pronounced."

But despite their 34 years together, Saint-Mars was reportedly no friend of the Man in the Iron Mask. Documents discovered in 2015 shed some light on the true story of the prisoner – and reveal that the jailer diverted the funds paid by King Louis XIV for the prisoner's maintenance into his own pocket. The prisoner's cell only contained a sleeping mat.

Among historians, there is agreement that this masked man existed, but it's not entirely clear what his mask was made of: some said black velvet, some said iron, and some said leather. It's even possible that the mask was only worn when the prisoner was being transferred from one prison to another, and that most of the time he was unmasked.

What are the theories surrounding the identity of the Man in the Iron Mask?

The Man in the Iron Mask's true identity has never been established, making this ripe territory for historical investigation – and conspiracy theories.

Was the Man in the Iron Mask actually King Louis' brother?

One leading theory was proposed by the writer and philosopher Voltaire. He was the first to claim in 1771 that the prisoner wore an iron mask (“the chin was composed of steel springs, which gave him liberty to eat with it on”). Voltaire also claimed that he was the older, illegitimate brother of Louis XIV.

Could he have been hidden away to prevent any claim on the throne? Or was this story Voltaire's invention?

The thinker had actually been imprisoned in the Bastille 15 years after the masked man's death, and claimed to have heard his story from the oldest prisoners. Apparently, the Man in the Iron Mask was refined, was served fine food, was musically talented and received no visitors.

Was the Man in the Iron Mask actually King Louis' father?

During the Nine Years' War, the Dutch encouraged claims that the masked prisoner was a former lover of the queen mother, making him the king's real biological father – and making Louis himself illegitimate.

There is some basis behind this theory. Louis was born very late in his parents' marriage, and they may have struggled to conceive. Did the Queen actually father the child with another man in order to provide a male heir?

Others suggested that he was Louis de Bourbon, Louis XIV's illegitimate son, who hadn't died on the battlefield at all and had instead been secretly imprisoned by his dad.

More plausibly, recent historians have suggested that the man could have been "Eustache Dauger", a man involved with several political scandals in the late 17th century. The details fit: he was first imprisoned in 1669 and held in the Fortress of Pignerol, and spent the rest of his life in various prisons – always in the company of jailer Saint-Mars.

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Was Philippe obsessed with him?

Probably not.

In Versailles, we see Philippe d'Orléans become obsessed by the Man in the Iron Mask – but this is an invented storyline for the TV show.

Speaking to RadioTimes.com, Alexander Vlahos explains: "When the writer came up to me and said that that was my storyline for the year, I thought: 'How are we going to realise this?' because obviously it's so steeped in mythology, no one really knows who that person was, and why he was there."

He teases: "It's an amazing spin on the mythology that the writers have introduced, and the issue spans the whole season. I think the reveal is going to be one that's not only shocking, but also very rewarding."

Wasn't The Man in the Iron Mask a film?

Yes: The Man in the Iron Mask is the title of a 1998 action movie, with Leonardo DiCaprio doubling up to play both Louis XIV and his identical secret twin brother.

This Hollywood movie draws on the work of French novelist Alexandre Dumas.

Dumas elaborated on Voltaire's theory in his novel The Vicomte of Bragelonne. According to his version, The Man in the Iron Mask was actually Louis XIV's identical twin brother who had been born first – and was therefore first in line to the throne. Louis had him imprisoned because he jeopardised his legitimacy as King.

Unfortunately we may never know the Man in the Iron Mask's true identity...

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