Around the time of King Louis XIV’s reign in France in the 17th century, there is a story of a mysterious man who had spent many years trapped behind the walls of several French prisons, including the Bastille as well as the Fortress of Pignerol. No one knew who he was or why he was put in jail. Over the centuries that passed, some even argued that no one had ever seen his face as this enigmatic prisoner had never spent a day of his life in prison without donning a black velvet mask that hid his true identity.

This unidentified inmate of several French prisons has been the subject of a variety of tales and legends, particularly in the written works of the likes of Alexandre Dumas and Voltaire, who actually popularized the idea that the prisoner’s mask was crafted from iron. And while the story of an imprisoned man wearing an iron mask seems one of fiction than fact, many historians are in agreement that such a man did exist in France several hundred years ago.

If this masked prisoner was indeed real, who was he and why did he have to wear a black mask? Over the years, dozens of potential personalities have been presented as the real man behind the iron mask, but experts have had a hard time universally agreeing on a single individual that could be his actual hidden identity.

And so for this video, we will explore some of these suggested personalities, speculated or real, and assess the likelihood of each one as the potential true identity of the legendary “Man in the Iron Mask.”

The Story of the Man Behind the Iron Mask

“L’Homme au Masque de Fer,” which in English translates to “The Man in the Iron Mask,” is arguably the most famous prisoner in French history. The earliest known record of this unidentified prisoner dates all the way back to July 1669.  In a letter from the Marquis de Louvois to Bénigne Dauvergne de Saint-Mars, the governor of the prison of Pignerol at the time, the minister mentioned that a prisoner named “Eustache Dauger” was going to be arriving the following month or so. The prison’s governor was told to make the necessary preparations for the prisoner’s arrival, and that Saint-Mars will be the one to oversee the immediate needs of the inmate by visiting only once a day. It was also mentioned in the letter that if the man said anything else apart from his daily needs, he would be executed. Louvois also noted that Dauger did not require a lot of attending to as he was “only a valet.”

While the name of the mysterious inmate was revealed in the letter as Eustache Dauger, no one knew for certain if this was his real name or was just a made-up name to ensure that his true identity stays never gets revealed. Much of the fascination over this individual largely stems from the rumor that his face had to be covered with a black velvet or an iron mask at all times while he was in jail, which naturally sparked the public’s interest and consequently gave rise to many theories and stories about who Dauger was.  It was also a wonder to many people how grave his crimes must have been that he was placed in a prison meant for those deemed to be an embarrassment to the state and why his jailers took extensive precautions to keep him imprisoned for more than three decades of his life in almost complete isolation.

The interesting tale of the man who was forced to wear an iron mask at all times led to various speculations, which were explored in works authored by the likes of Voltaire in “Le siècle de Louis XIV” and Alexandre Dumas in “The Vicomte de Bragelonne.” For example, some believed that the masked prisoner was nothing more than just a lowly servant who probably saw something he should not have seen, or whose physical appearance displeased the king. There were those, however, who believed that there was so much more to the identity of this prisoner, going so far as to claim that he was someone of royal blood whose face had to remain unseen as he bore a strong resemblance to another individual already in power at the time.

Illegitimate Half-Brother or Twin Brother of King Louis XIV

One of the popular theories about the lineage of the masked prisoner was initially suggested by Voltaire, who claimed that “The Man in the Iron Mask” was the older, illegitimate half-brother of King Louis XIV, and was the son of Anne of Austria and Cardinal Mazarin. Dumas worked on a similar theory in his book but with one substantial change: the prisoner was not just the half-brother of King Louis XIV but was his older identical twin, making him the legitimate king of France. As the story goes, the king’s brother had to be kept hidden as his existence would raise a serious and chaotic issue about succession. But since a prince with royal blood is not allowed to be killed, he had to spend the rest of his days in prison while wearing a mask the entire time to hide his striking resemblance with the reigning king.

Real Father of King Louis XIV

There was also a suggestion that the imprisoned man in the iron mask was actually the biological father of King Louis XIV. According to this particular theory, Louis XIV’s miraculous birth came at a time when Louis XIII was already very old, sickly and possibly impotent, which implies that he may not have been capable of fathering a child at the time that Louis XIV’s was conceived.

Before the birth of Louis XIV, the heir presumptive to the throne of France was Gaston d’Orléans, the brother of King Louis XIII. Neither the king nor the queen was fond of Gaston. The queen, in particular, did not see it as in her best interests to allow Gaston’s ambition to ascend as the next king as she knew he would surely suppress her influence and power. And so, through the machinations of Cardinal Richelieu, the king’s minister and an enemy of Gaston d’Orléans, a substitute was selected to impregnate the queen and father an heir to the throne in the king’s stead.

After escaping to the Americas, this substitute supposedly returned to France in the 1660s and tried to extort money in exchange for keeping the secret that he was King Louis XIV’s real father. To protect the legitimacy of Louis XIV’s claim to the throne, the man was immediately arrested. However, out of respect for his biological father, the king allegedly could not bring himself to order the man’s execution and have chosen comfortable imprisonment as a more suitable punishment instead.

General Vivien de Bulonde

Another theory about the true identity of “The Man in the Iron Mask” came from the Great Cipher of Louis XIV, which was decrypted by Etienne Bazeries of the French Army’s cryptographic department around the 1890s. One of the decoded messages mentioned of a prisoner named General Vivien de Bulonde, who supposedly angered the king for his cowardice during the siege of Cuneo back in 1691. Out of fear of the approaching troops from Austria, de Bulonde ordered the hasty withdrawal of the army, leaving behind supplies and injured soldiers in the process. This enraged the king, who ordered the general’s arrest and imprisonment at the fortress of Pignerol.

It is difficult to determine whether Bulonde really was the iron-masked inmate especially since Bulonde’s arrest was not a secret and was actually reported in the newspaper around that time. Moreover, his death has been recorded to have taken place in 1709, which is six years later than the reported death of the masked prisoner in 1703.

Count Ercole Antonio Mattioli

Another famous candidate believed to be “The Man in the Iron Mask” was Count Ercole Antonio Mattioli, an Italian diplomat, and minister of Ferdinand Charles, the Duke of Mantua. Mattioli was entrusted in securing the sale of the fortified town of Casale in 1678. However, after he secured his earnings from the agreement, Mattioli betrayed France by leaking the details of the treaty to the country’s Spanish enemies, which thwarted France’s plans to successfully occupy the town. Infuriated over Mattioli’s treachery, the king ordered for Mattioli’s abduction and was subsequently imprisoned in Pignerol in April 1679.

Because the masked man is known to have been buried under the name “Marchioly,” this led many to believe that Mattioli and “The Man in the Iron Mask” are the same. However, it is generally agreed on by many experts that Mattioli passed away in Îles Sainte-Marguerite back in April 1694, several years before the death of Eustache Dauger.

Eustache Dauger de Cavoye

One of the more compelling theories about the identity of “The Man in the Iron Mask” is that Eustache Dauger is actually Eustache Dauger de Cavoye, the son of a captain who served as one of Cardinal Richelieu’s guards. Born in 1637, Eustache joined the royal army but was forced to resign his commission in disgrace after he ended up killing a young page boy during a drunken brawl. During his incarceration, Eustache supposedly complained of how he was treated in prison in 1678, and the king subsequently issued an edict that he was no longer permitted to speak to anybody unless in the presence of a priest.

While Eustache Dauger De Cavoye seemed like the most likely candidate to be “The Man in the Iron Mask,” evidence has emerged that Dauger De Cavoye met his demise in the Prison Saint-Lazare in the 1680s, several years before the death of the famous Eustache Dauger in Îles Sainte-Marguerite in 1703.

Perhaps the most recent theory about the identity of the masked prisoner in 17th-century France is presented by Paul Sonnino, a history professor at UC Santa Barbara, in his 2016 book, “The Search for the Man in the Iron Mask: A Historical Detective Story.” According to Sonnino’s book, Dauger was, in fact, the valet of the treasurer of Cardinal Mazarin, a principal minister in France during the early life of Louis XIV.  Mazarin amassed a huge fortune during his lifetime, which led the valet to believe that some of the minister’s money may have been stolen from the previous king and queen of England. When he was arrested, he was warned not to reveal his real identity to anyone unless he wanted to be executed immediately.

When “The Man in the Iron Mask” passed away on November 19, 1703, at the Îles Sainte-Marguerite and was buried the following day with the name “Marchioly,” all his possessions in his cell, including his furniture and clothing, were all burned. Everything he owned that were made of metal was melted down. And the walls of his cell were scraped clean, leaving no trace of the inmate that once spent many years of his life in confinement and isolation.

With so many theories on who he really was and speculations on whether or not he was actually guilty of a crime worthy of lifetime incarceration, we may never really know the reason why this famous prisoner had to wear an iron mask while in almost complete isolation in prison. For all we know, Eustache Dauger was just an ordinary citizen who slighted the king and had the unusual punishment of having to wear a mask while living the remainder of his life inside a cell. It probably never even crossed his mind that his life of incarceration would be a subject of intrigue and mystery that managed to capture the interest of countless people even until today.




  1. Well, of course, as any good scientist will tell you, we do not ever REALLY know anything. All scientific knowledge is practical and based on varying degrees of probability. Thus evaluating a thesis by claiming that we will never “really” know is a rhetorical cop out

    Thanks for the publicity though.

    Paul Sonnino