Three hundred years ago, before envelopes, passwords, and security codes, writers often struggled to keep the thoughts, worries, and dreams expressed in their letters private.
A popular way was to use a technique called letter blocking – the complicated folding of a flat sheet of paper to become your own envelope. This security strategy posed a challenge when 577 locked letters delivered to The Hague in the Netherlands between 1689 and 1706 were found in an undelivered mail trunk.
The letters had they never reached their final recipients, and the conservatives did not want to open and destroy them. Instead, a team found a way to read one of the letters without breaking or sealing it. Using an extremely sensitive X-ray scanner and computer algorithms, the researchers carried out the virtually unopened letter.
This is a computer-generated sequence of a sealed letter from seventeenth-century Europe. Virtual deployment was used to read the contents of the letter without physically opening it. Credit: Kindness of the Unlocking History Research Group archive
“This algorithm takes us directly to the heart of a blocked letter,” the research team said in a statement.
“Sometimes the past opposes control. We could have simply cut these letters open, but we took the time to study them for their hidden, secret, and inaccessible qualities. I have learned that letters can be much more revealing when left open. ”
The technique revealed the contents of a letter dated July 31, 1697. It contains a request by Jacques Sennacques to his cousin Pierre Le Pers, a French merchant in The Hague, for a certified copy of a death notice of Daniel Le Pers.
The details may seem prosaic, but the researchers said the letter offers a fascinating perspective on ordinary people’s lives – a snapshot of the early modern world as it unfolded.
This trunk of undivided letters from the 17th century was bequeathed to the Dutch Postal Museum in The Hague in 1926. A letter from this trunk was scanned by X-ray microtomography and practically unfolded to reveal its contents for the first time in centuries. . Credit: Kindness of the Unlocking History Research Group archive
In addition to the unopened letters, it contains 2,571 open letters and fragments that for one reason or another never reached their destination.
At that time, there was no postage stamp, and the recipients, not the senders, were responsible for postage and delivery charges. If the addressee has died or rejected the letter, no fees may be charged and the letters have not been delivered.
A new way to extract historical documents
X-ray scanners were originally designed to map the mineral content of teeth and have been used in dental research – until now.
“We managed to use our scanners for the history of radiography,” study author David Mills, a researcher at Queen Mary University in London, said in a statement.
“The scanning technology is similar to medical CT scanners, but using much more intense X-rays, which allow us to see the tiny traces of metal in the ink used to write these letters. The rest of the team was then able to scan our images and turn them into letters that they could open virtually and read for the first time in over 300 years. “
The letter contains a message from Jacques Sennacques dated July 31, 1697 to his cousin Pierre Le Pers, a French merchant. Also visible is a watermark in the center that contains an image of a bird. Credit: Kindness of the Unlocking History Research Group archive
The new technique has the potential to unlock new historical evidence from Brienne’s trunk and other collections of unopened letters and documents, the study said.
“Using virtual deployment to read an intimate story that never saw the light of day – and never even reached the recipient – is truly extraordinary,” the researchers said in a statement.
The research was published Tuesday in the journal Nature Communications.