What started with a music historian reading a short notice in a 1938 French journal about undelivered 17th-century letters in The Hague has blossomed into an international collaboration focusing on thousands of letters that paint a vivid picture of life in early modern Europe.

The project, titled “Signed, Sealed, and Undelivered,” is an international public-private partnership between researchers from five leading universities — Yale, Massachusetts Institute of Technology, and the Universities of Leiden, Groningen, and Oxford — and the Museum voor Communicatie in The Hague. The project centers on an archive of undelivered letters — many of them unopened — sent from across Europe to The Hague between 1689 and 1707. There are 2,000 opened letters and 600 letters that are still sealed. These letters were acquired by the museum in 1926, in the original trunk once belonging to Simon de Brienne and his wife, Maria Germain, who were postmasters in The Hague from 1676 until 1707.

In 2012, Rebekah Ahrendt, assistant professor of music at Yale was tracking a theater troupe that worked in The Hague at the turn of the 18th century and came across a short notice that described a collection of undelivered letters at the postal museum and included transcriptions of seven of them. The music historian did some legwork to determine which museum had the letters and was able to track down the curator.

“The letters that were in the trunk were a sort of postal piggybank. It just blew my mind,” Ahrendt says.

In addition to Ahrendt, the team working on the “Signed, Sealed, and Undelivered” project includes David van der Linden (University of Groningen), Nadine Akkerman (University of Leiden), Jana Dambrogio (Massachusetts Institute of Technology Libraries), Daniel Starza Smith (Lincoln College, University of Oxford), and Koos Havelaar (Museum voor Communicatie, The Hague).

“One of the great things about this collaboration,” says Ahrendt, “is that we have the curator of the collection, a professional conservator, and academics, and we can all learn from each other. And this research is right in line with the courses that I already teach.”

The archive was established by the postmasters in an attempt to profit from their business. At that time, recipients were responsible for paying for any letters they received, and if the letters were undelivered, the postmasters would keep them in the hope that someday the recipient would search for the letter and pay them what was owed. The letters were stored in a trunk that had been waterproofed with sealskin. “Somehow, these letters managed to survive all these years,” Ahrendt says. “This collection challenges our notion of what an archive is because it was never intended to be one,” says Ahrendt, adding, “It came together by accident.”

The trunk also contains elaborate accounting books for both incoming and outgoing posts, which detail the prices for correspondence centuries ago.

“We discovered how postal routes and the financial system of that time worked. There is documentation of the point at which you paid a rider or a boatman to transport your post. We learned about the connection between the post office in Hague and the post office in Paris. We even found nasty letters from the Parisian postmaster saying that he hadn’t been paid properly,” says Ahrendt.

The team was astounded by the sheer volume of correspondence that went back and forth, says Ahrendt. “What is within the letters are amazing stories — some about broken hearts and a few that seem to be hinting at something that you would not speak of out loud.”

Ahrendt describes a letter written by a woman on behalf of a friend who is an opera singer. The letter is addressed to a wealthy merchant in The Hague and reads: “I am writing on behalf of your friend and mine and she realized as soon as she left the opera company in The Hague to go to Paris that she had made a terrible mistake. Now she needs your help to come back to The Hague. I could tell you the true cause of her pain, but I think you can guess.”

According to Ahrendt, the postmaster’s office would record the reason that a letter wasn’t delivered. “A letter might be marked ‘moved to England’ or ‘dead.’ This one is marked ‘refused.’”

Many of the letters have items tucked into them, such as religious tokens or business samples. One letter — an example of an early form of marketing — contains a sample page of many different types, colors, and gauges of thread. Each of the threads was painstakingly pasted onto the page with a wax seal.

As a music historian, Ahrendt found the correspondence between musicians especially interesting and says the information these missives contain casts a different light on the development of the musical labor industry: “This archive is truly a cultural history of musicians. I was surprised to learn that musicians traveled so much during that time period. We have so few witnesses to describe what daily life was like for your average musician, and these letters tell of large networks of these musicians traveling frequently. This is completely different from what we previously believed about the history of musicians.”

Even the unopened letters have stories to tell. Dambrogio has been studying the method that the senders used to secure the letters and has coined the term “letterlocking.” Dambrogio and the team are looking for a correlation between the various formats and the contents of the letters, and are creating a dictionary to describe the specific formats that people used and why. For instance, explains Ahrendt, if the missive is folded one way it is more likely to be a love letter because it is more esthetically pleasing than secure, and one with a fold that is more difficult to open is likely to be a spy letter because of the various layers of security built into it. “The materials used to secure the unopened letters are just as important as the contents within,” notes Ahrendt.

The team is researching various scanning techniques that would allow them to see inside of the letters without actually opening them. “The next step of our work is to connect the cultural history aspect of the project with science and technology so that we can realize our vision,” says the music historian.

The letters were written in six languages and have presented a linguistic challenge for the team. Also, the handwriting is “chaotic,” notes Ahrendt. “Many of these people are only barely literate. Some hired professional letter writers, but most of them are written by average people spelling phonetically in their own dialects.”

Ahrendt says that the letters are a “tape recording” of how people sounded at the time and that she read them aloud in order to understand the contents. At that time if you received a letter it was expected that you would share your correspondence so the letters include greetings to friends and family, she notes. “This material generated an almost unconscious response in me that I imagine the person 300 years ago — if they had actually received the letter — would have felt.”