X-rays reveal censored portions of Marie Antoinette’s letters to Swedish count

Many people associate Marie Antoinette's affair with the diamond necklace. The French Revolution. Louis XVI was the husband of the French queen. They were executed 10 months apart in 1793. Her colorful life included a possible love affair with a Swedish count. History has been trying to unravel the letters between them for many years.
As was customary for politically sensitive correspondence at that time, the letters were cyphered. 15 of the letters surviving in the French National Archives collection have significant redacted portions, totaling 108 illegible line. A new paper in Science Advances reports that eight of the letters were finally revealed thanks to cutting-edge data processing and x-ray imaging. This research was done in collaboration with the National Archives, French Museum of Natural History and Fondation de France.

Marie Antoinette met Count Hans Axel von Fersen from Sweden as teenagers at a masquerade party, while she was still Dauphine in France. He became a frequent visitor of Versailles after that. Famously, her royal husband was unable to consummate their marriage within seven years.

There was speculation that Louis XVI suffered from a medical condition. However, Holy Roman Emperor Joseph II, the queen's brother, said that the king's inexperienced and lack of interest were the main reasons. The emperor described them as "complete bumblers" and the young kinglet's say that his letters back to him included very candid references to the "soaking" rumored to be a Mormon practice.

The couple eventually figured it out, and Marie Antoinette had four children. Only one of them survived to adulthood. Rumours of her infidelity were already circulating, and von Fersen was rumored to be one of her lovers. (Other potential candidates include the Duc d'Orleans or the Comte d'Artois. They were definitely close. In 1780, von Fersen asked for a transfer to America as an aide de camp to General Rochambeau. He fought bravely at the Siege in Yorktown. He returned to France in 1780 as the Swedish ambassador to Versailles and was a part of the queen’s inner circle.


The French Revolution erupted in 1791 and the royal family was placed under house arrest at Tuileries Palace. The loyal von Fersen was a key figure in devising the plan for the failed escape that saw the royals taken back to Varennes, where they were held until they found safety. The exchange of letters between the queen and count took place during this period.

Von Fersen was visiting Brussels when he learned that Marie Antoinette was being executed. He declared himself "devastated" to the idea that he might have doubted her attachment to him. He survived the Revolution, but he also died violently. A mob from Sweden beat him to death believing he was responsible for the death of the Swedish Crown Prince. He wasn't.

Researchers may be able to read portions of redacted letters, which could allow them to decipher other defaced or censored historical documents. The ability to study fragile artifacts from the past using cutting-edge, noninvasive imaging technology is a powerful tool in unlocking the secrets of our past. We've previously reported that in 2016, a team of international scientists devised a method to "virtually roll" the En Gedi scroll, which was badly damaged and found on the Dead Sea shore. This revealed the first verses of the Book of Leviticus.

A team of German scientists combined cutting-edge physics techniques with a combination to "unfold" an ancient Egyptian Papyrus. This papyrus is part of a large collection at the Berlin Egyptian Museum. The analysis revealed that the papyrus' seemingly blank area actually contained characters in invisible ink, which had been exposed to light for centuries. Researchers were able to perform a virtual postmortem using micro CT imaging in 2020 on the remains of an Egyptian cat mummified.

We reported earlier this year that scientists used multispectral imaging to examine four apparently blank Dead Sea Scrolls. They found hidden text in the scrolls, most likely from the Book of Ezekiel. Researchers also used xray tomography in order to "unlock" an 17th-century letter sealed with an intricate folding process known as "letterlocking," which is a form of physical cryptography to protect the contents.

Fabien Pottier, along with several colleagues from the Museum of Natural History’s Research Center for the Conservation of Collectionss (CRCC), took on the task of discovering the censored parts of letters between Marie Antoinette & von Fersen. They naturally used similar techniques. It was necessary to separate the ink that was used to black out the text from the original ink. The first stage involved testing different techniques that could distinguish between the chemical and physical properties of the inks. This was to determine if enough contrast was possible to separate them.


Initial results for hyperspectral imaging in both the near-infrared and visible ranges looked promising. The black redaction ink was unable to absorb nearly all visible light, while the NIR ink was largely transparent. Both were too similar for conclusive results. Pottier and his colleagues achieved the best results using X-ray fluorescence spectroscopy (XRF) in a microscanning mode. Their preliminary analysis revealed that all letters (and redactions!) were written with metal-gallink. While the main metal component is iron, other metals (copper, zinc, and others) can be introduced during ink preparation. These impurities can be used to identify different inks.

Although the XRF imaging produced useful elemental maps, the team still had to use some custom imaging processing in certain cases to read redacted text. This included instances where redacted passages were written both on one side of the paper. Thus far, Pottier et al. Pottier et al. have "de-censored" eight of the 15 redacted letters.

The authors stated that the remaining seven letters were redacted. "All the methods that have been presented failed to recover any of the censored writings." "In these cases both the inks (redaction) and the underlying text seem to have similar compositions making it difficult to read the redacted passages through the data processing described here.

They were able to determine that von Fersen likely censored these letters and that von Fersen's queen's letters to von Fersen had been copies of the count's (a common practice in that era). The authors stated that von Fersen decided to keep his letters rather than destroy them. However, he redacted some sections to show that he wanted the honour of the queen (or perhaps also for his own interest). These redactions were made to identify passages he considered private.

Scholars are still trancribing the paragraphs that were once redacted. Fersen wrote a letter dated October 10-12 1791. It contained the words "Goodbye, my dear friend. I will never stop worshipping and loving you." Although there are many instances of the same vocabulary in the letters ("beloved," tender friend," "adore," and "madly"), it is hard to imagine a passionate attachment. However, the authors do not overestimate the evidence.

They wrote that "To read under censorship does NOT make it possible for you to know the truth about their feelings because the interpretation of texts are always questionable." This correspondence is a valuable testimony to a troubled period and to the influence of tragic political events on the transformation of emotions and exacerbation, particularly in these personal writings.

DOI: Science Advances 2021. 10.1126/sciadv.abg4266 (About DOIs).