More than 600 years ago, someone folded, sealed, and published a letter that was never delivered. Now, scientists have digitally “deployed” this and other similarly blocked letters that were found in a 17th-century trunk in The Hague, using X-rays.
For centuries prior to the invention of sealed envelopes, sensitive correspondence was protected from prying eyes by complex folding techniques called “letter blocking,” which transformed a letter into its own secure envelope.
However, the blocked letters that survive so far are fragile and can only be physically opened by cutting them into pieces.
The new X-ray method offers researchers a non-invasive alternative, which retains the original folded shape of a pack of cards.
For the first time, scientists applied this method to the “closed” letters of the Renaissance period, kept in a trunk that since 1926 was in the collection of the Dutch Postal Museum in The Hague (Netherlands).
Computer-generated drop-down animation of the stamped letter DB-1538. (Unlock History Research Group Archive)
Related: Photos: Treasure of unopened letters from the 17th century
The contents of the trunk include more than 3,100 undelivered letters, of which 577 were unopened and blocked. Known as the Brienne Collection, the letters were written in Dutch, English, French, Italian, Latin and Spanish.
For unknown reasons, once the letters arrived in The Hague, they were never delivered to the intended recipients, but were kept by a postmaster named Simon de Brienne, Live Science reported.
Blocked letters used different mechanisms to stay tightly closed, including folds and rolls; cracks and holes; tucks and stickers; and a variety of cleverly constructed locks, according to a study published online March 2 in the journal Communications on Nature.
To penetrate the folded paper layers, the study authors used an X-ray microtomography scanner designed in the dental research laboratories of Queen Mary University of London (QMU).
The researchers designed the scanner to be exceptionally sensitive so that it could map the mineral content of the teeth, “which is invaluable in dental research,” said study co-author Graham Davis, a professor of imaging. 3D X-rays of the QMU.
“But this high sensitivity has also made it possible to solve certain types of ink on paper and parchment,” Davis added.
The trunk was filled with sealed letters. (Unlock History Research Group Archive)
“The rest of the team was able to take our scan images and turn them into letters that they could virtually open and read for the first time in over 300 years,” said study co-author David Mills, responsible for QMU’s X-ray microtomography facilities, said in the statement.
From the scans, the team built 3D digital reconstructions of the letters and then created a computational algorithm that deciphered the sophisticated folding techniques, folding by folding, opening the letters virtually “while retaining evidence of blocking letters ”, according to the study.
Scientists digitally opened four letters with this innovative method, deciphering the contents of a letter, the DB-1627.
Hanged on July 31, 1697, it was written by a man named Jacques Sennacques to his cousin Pierre Le Pers, who lived in The Hague. Sennacques, a legal professional in Lille, France, applied for an official death certificate for a relative named Daniel Le Pers, “perhaps because of a question of inheritance,” the scientists wrote.
“After her request, Sennacques spends the rest of the letter asking for news from the family and recommending her cousin by the graces of God,” the authors wrote. “We don’t know exactly why Le Pers didn’t receive the letter from Sennacques, but given the roaming of the merchants, it’s likely that Le Pers has continued.”
(Unlock History Research Group Archive)
Researchers reported that virtually tens of thousands of sealed documents can now be deployed and read.
“This algorithm takes us directly to the heart of a blocked letter,” the research team said in the statement. “Using virtual deployment to read an intimate story that has never seen the light of day – and that has not even reached its recipient – is truly extraordinary.”
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This article was originally published by Live Science. Read the original article here.