Jacques Sennacques of Lille, France, wrote a missive to his merchant nephew, Pierre le Pers, in The Hague, in July 1697. The topic of conversation was a death certificate for a mother, which the cousins had previously mentioned but le Pers had failed to follow up on. The letter was the Renaissance version of an “As I stated in my previous email,” and it had just recently been opened for the first time in 324 years.
Prior to the invention of sealed envelopes, confidential correspondence was shielded from prying eyes for centuries by using complicated folding techniques known as “letterlocking,” which turned a letter into its own safe envelope. Locked letters that have survived to the present day, on the other hand, are delicate and can only be opened physically by slicing them to bits.
The Renaissance chest contains missives from around the world sent to The Hague.
© Courtesy of the Unlocking History Research Group archive.
With Daniel Starza Smith, a professor in early modern English literature at King’s College London, and the Unlocking History research team, Jana Dambrogio, the Thomas F. Peterson Conservator at MIT Libraries, established letterlocking as a field of study.
“Letterlocking has been a common practice for decades, spanning cultures, boundaries, and social classes,” Dambrogio notes. “It is an important part of the history of secrecy systems because it is the missing link between ancient physical communications security strategies and modern digital cryptography. This Renaissance investigation leads us straight into the heart of a sealed letter.” In the MIT News Article.
It’s unclear why le Pers never received the letter; considering his occupation, he should have relocated. The sealed note, however, remained in the hands of Simone de Brienne, the chief postmaster of The Hague, and his wife, Marie Germain. The couple didn’t throw away the enclosed family correspondence because letters during the renaissance were bought by receivers rather than senders at the time. Some postmasters kept unclaimed letters in the hopes that someone would come along and purchase them later.
In an email, co-lead author Amanda Ghassaei, the algorithm engineer lead on the renaissance project and who previously worked on simulating the folds in origami, said, “We start with a very high-resolution CT scan of the folded letterpacket, basically a 3D x-ray image.” “Our algorithm then reconstructs the folded geometry by detecting individual layers of paper in the scan. Without causing any harm to the original artifact, this computational pathway helps us to observe printing, watermarks, seals, internal folds, and whatever other details concealed within the letterpacket.”
The Process Visualized We can’t paste this image from the Clipboard, but you can save it to your computer and insert it from there.
“We only know the message and complex internal mechanics of these letters since they have been digitally reconstructed,” said co-author Holly Jackson, an MIT undergraduate who worked on the project as an algorithm engineer. “Our methods are completely automated, impartial to scan location, and do not require any previous knowledge of the folded geometry of a letterpacket.”
The team of renaissance researchers includes Jana Dambrogio, Thomas F. Peterson Conservator, MIT Libraries; Amanda Ghassaei, a research engineer at Adobe Research; Daniel Starza Smith, a professor in early modern English literature at King’s College London; Holly Jackson, an undergraduate student at MIT; Erik Demaine, a professor in EECS; Martin Demaine, robotics engineer in CSAIL and Angelika and Barton Weller Artist-in-Residence in EECS; Graham Davis and David Mills, Queen Mary University of London’s Institute of Dentistry; Rebekah Ahrendt, associate professor of musicology at Utrecht University; Nadine Akkerman, reader in early modern English literature at Leiden University; and David van der Linden, assistant professor in early modern history at Radboud University Nijmegen.