This is a discovery that would not have displeased the cohorts of spies who roamed the European courts of the Renaissance and the Enlightenment.
A team of international researchers led by Jana Dambrogio, curator of MIT libraries, has developed a new technique for reading - without opening them - sealed letters from modern times.
Published on March 2 in the journal
Nature Communications
, their study reviews in detail the procedures used to overcome the letter-writing confidentiality of 17th century Europeans.
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At the origin of the whole adventure, the scientists - united in the Unlocking History Research Group - relied on a precious chest kept at the Postal Museum in The Hague.
Former possession of the Flemish postmasters Simon de Brienne and Marie Germain.
Died in 1707 and 1703, the two Dutch left in this cassette 3,148 letters from the end of the 18th century and the beginning of the 18th century, of which 577 were never opened.
A boon for researchers interested in precisely non-invasive ways of reading modern-day mail.
The task was already a real headache for the intelligence services of pre-industrial Europe.
1/3 - The Dutch chest from the end of the 17th century, one of the closed letters studied, and the digital modeling unfolded.
The Brienne Collection / Sound and Vision / Unlocking History Research Group archive
2/3 - The Dutch chest from the end of the 17th century, one of the closed letters studied, and the digital modeling unfolded.
The Brienne Collection / Sound and Vision / Unlocking History Research Group archive
3/3 - The Dutch chest from the end of the 17th century, one of the closed letters studied, and the digital modeling unfolded.
The Brienne Collection / Sound and Vision / Unlocking History Research Group archive
If it was already possible to decipher the contents of a letter folded only once or twice, getting hold of the text of a letter folded more than three times in addition to being sealed was a challenge and could not even be done. 'then be realized that by means of a careful cut, as slow as risky for the information of the missive.
The international team therefore carried out a scrupulous study of nearly 250,000 handwritten letters which made it possible to identify twelve different types of closures.
From there, and using a powerful X-ray scanner - sensitive to the metal of inks - researchers devised a new
"fully automatic computing approach
" of "
virtually reconstructing and unfolding volumetric scans"
using a algorithm.
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And the first results were not long in coming: four closed letters from the Dutch safe, dated from 1680 to 1706, were thus able to be deciphered without being opened.
One of them, sent from Lille by Jacques Sennacques on July 31, 1697 to her cousin, a French merchant in The Hague, requested a copy of a death certificate as well as news of the state of health of her. recipient.
Remarkable, this new method shines by its speed, only a few days - and a few hours, eventually - where the opening of a letter could take years.
Finally, its non-intrusive qualities help preserve the integrity of these fragile historical documents.
“We really need to preserve the original letters as best we can,”
Jana Dambrogio told The
New York Times
.
“
We can continue to learn from these letters, even and especially if we keep these packages closed.
”Enough therefore to keep intact all the letters of the Republic of Letters preserved in the collections of the world.
A great discretion that the Chevalier d'Éon would not have denied in his time.