An X-ray fluorescence scanner analyzes correspondence of Marie Antoinette and Fersen at France’s National Archives.
Centre de Recherche sur la Conservation, French National Museum of Natural History

I will finish not without telling you my dear and loving friend that I love you madly and that I can never be a moment without adoring you.”

During the dangerous days of the French Revolution, in January 1792, Marie Antoinette, queen of France, closed a letter with these tender words. But that letter was not meant for her husband Louis XVI. Instead, her intimate friend and rumored lover Swedish count Axel von Fersen was the recipient.

The pair’s relationship demanded discretion. So did political aspects of their correspondence. The letters were exchanged while the royal family was being held under house arrest by the revolutionaries controlling France. Both Marie Antoinette and Fersen were pulling political strings in the hopes of salvaging the Bourbon dynasty, or at least saving the royals’ lives. For one or both of these reasons the few surviving letters between them are sprinkled with passages, like the one above, that have been blotted out by some unknown censor. By blacking over words and entire lines with dark ink someone meant to hide them forever from history and they succeeded for two centuries—until now.

Modern technology has foiled some of the censor’s efforts. Anne Michelin, a physical chemist at the French National Museum of Natural History and colleagues have used old fashioned hard work and new techniques that plumb the varied composition of different inks to uncover many redacted parts of this famed correspondence. In doing so they believe they’ve also revealed who wielded the heavy-handed pen. The mystery censor appears to have been Fersen himself. Michelin’s study, published today in Science Advances, also demonstrates a methodology that may recover countless historical correspondences, official papers and drawings—and it might even help to analyze fossils.


A side-by-side comparison shows an original letter with redactions (left) and the same letter examined using a combination of X-ray fluorescence imaging and data processing (right).

Centre de Recherche sur la Conservation, French National Museum of Natural History

Between June 1791 and August 1792 the French royal family lived under a form of house arrest at the Tuileries Palace in Paris while Fersen was abroad. Their confinement followed a disastrous failed attempt to escape Paris orchestrated in large part by Fersen. The royals hoped to rally supporters in rural France and seize power from the revolutionaries. Instead, the family’s flight and arrest at Varennes turned popular opinion decidedly against them and opened them to charges of treason. During this period, while under heavy guard, Marie-Antoinette conducted a complicated correspondence with Fersen. Letters were delivered by intermediaries but also hidden by extravagant precautionary methods including invisible ink and codes that required complicated deciphering.

Marie-Antoinette even complained about the process to Fersen on November 2, 1791, writing “Farewell, I am getting tired of ciphering; this is not my usual occupation and I am always afraid of making mistakes.”

Secrecy was critical for several reasons and historians have long wondered who crossed out various parts of the text. The influential Fersen had fled France after his role in the failed escape was discovered. In Brussels, Vienna and elsewhere he desperately lobbied to influence foreign powers, including relatives of the royals, who might help to restore them to the throne or otherwise aid their plight. Such political intriguing, mentioned in the letters, would have been considered a deadly serious crime by the revolutionaries.



By Harry