A team cracked the Mary, Queen of Scots' hidden message letters

A team of international codebreakers managed to uncover the letters penned by Mary, Queen of Scots, while she was imprisoned in England by her cousin Queen Elizabeth I. The letters were thought to be lost for centuries.

As stated in the release, physicist and patents specialist Satoshi Tomokiyo, pianist and music professor Norbert Biermann, and computer scientist and cryptographer George Lasry came across them while looking for encrypted documents in the Bibliothèque nationale de France (BnF) online archives. After solving her sophisticated cipher system, the trio only discovered Mary was the author.

Including works of 57 letters dating from 1578 to 1584, their decipherment was published in Cryptologia. The letters revealed that Mary's letters were primarily addressed to the French ambassador to England, Michel de Castelnau de Mauvissière. He supported Mary, a Catholic who penned them while in the care of the Earl of Shrewsbury.

The study's authors used both manual and computerized methods to decipher the letters, revealing the difficulties Mary had in keeping in touch with the outside world and how and by whom the letters were transported.

"Upon deciphering the letters, I was very, very puzzled, and it kind of felt surreal. We have broken secret codes from kings and queens previously, and they're very interesting, but with Mary Queen of Scots, it was remarkable as we had so many unpublished letters deciphered and because she is so famous," says lead author Lasry.

"Together, the letters constitute a voluminous body of new primary material on Mary Stuart – about 50,000 words in total, shedding new light on some of her years of captivity in England," he added.

"Mary, Queen of Scots, has left an extensive corpus of letters held in various archives. There was prior evidence. However, that other letters from Mary Stuart were missing from those collections, such as those referenced in other sources but not found elsewhere.

Why did she write these letters?

"The letters we have deciphered … are most likely part of this lost secret correspondence," stated Lasry.

Mary made great efforts to enlist couriers and maintain secrecy in contacting her friends and allies when she was imprisoned. Historians and English authorities knew that Mary and Castelnau had a private communication line.

The main subjects of Mary's letters are her concerns about her ill health and the conditions of her captivity, as well as her talks with Queen Elizabeth I for her release, which she feels are not done in good faith.