Secret letters written by Mary Queen of Scots while imprisoned in England by her cousin Queen Elizabeth I have been decrypted.
Experts said the codebreakers’ work is the most important discovery about Mary in 100 years.
For centuries it was believed that the contents of the letters had been lost.
That was until George Lasry, a computer scientist and cryptographer, Norbert Biermann, a pianist and music professor, and Satoshi Tomokiyo, a physicist and patent expert, came across them at the National Library of France – Bibliotheque nationale de France (BnF).
The trio discovered that Mary had written the letters after solving her numeral system.
Their work on 57 letters revealed 50 new scripts that historians were unaware of.
The letters date from 1578 to 1584, a few years before the beheading of Mary 436 years ago today – February 8, 1587.
According to the decoders, the letters reveal fascinating insights about her imprisonment.
Most are addressed to Michel de Castelnau de Mauvissiere, the French ambassador to England, who was a supporter of the Catholic Mary.
Mr Lasry, lead author of the study, said: “When I deciphered the letters I was very, very amazed and it felt a bit surreal.
“We’ve broken secret codes of kings and queens before, and they’re very interesting, but with Mary Queen of Scots it was remarkable because we’d deciphered so many unpublished letters and because she’s so famous.
“This is a really exciting discovery.”
As part of the multidisciplinary Decrypt Project involving several universities in Europe, with the aim of mapping, digitizing, transcribing and deciphering historical ciphers, he added: “Together, the letters constitute a voluminous body of new primary material about Mary Stuart – about 50,000 words in all, shedding new light on some of her years of imprisonment in England.
‘Mary, Queen of Scots, left an extensive corpus of letters in various archives.
“However, there was earlier evidence that other letters from Mary Stuart were missing from those collections, such as those referenced in other sources but not found anywhere else.
“The letters we have deciphered… are most likely part of this lost secret correspondence.”
While in captivity, Mary communicated with her associates and allies and made extensive efforts to recruit messengers and maintain secrecy.
The existence of a confidential channel of communication between Mary and Castelnau is well known to historians and even to the then English government.
But the codebreakers provide new evidence that this exchange was in effect as early as May 1578 and active until at least mid-1584.
Computer and manual techniques were used to decode the letters that reveal the challenges Mary faced in maintaining ties with the outside world, how the letters were carried and by whom.
Major themes of the correspondence include complaints about her poor health and captive conditions, and her negotiations with Queen Elizabeth I for her release, which she says were not conducted in good faith.
The letters reveal her distrust of the Queen’s spymaster, Sir Francis Walsingham, as well as her animosity towards Robert Dudley, Earl of Leicester and a favorite of Elizabeth’s.
She also expresses her grief when her son James (future King James I of England) is kidnapped in August 1582, and that she feels they have been abandoned by France.
In this Special Issue version of Cryptologia, the authors describe how some letters in a large series of unmarked documents were ciphered and used the same set of graphic symbols.
The BnF catalog listed them from the first half of the 16th century and related to Italian affairs.
However, the study’s authors say that shortly after they started cracking the code, they soon realized they were written in French and had nothing to do with Italy.
Their work revealed verbs and adverbs often in the feminine form, several mentions of captivity, and the name “Walsingham”, suggesting that the documents may have been written by Mary, Queen of Scots.
This was confirmed by comparing them with the plain text of letters in Walsingham’s papers in the British Library and by other methods.
A search for similar letters in BnF collections revealed 57 with the same number.
Commenting on the new article, Mary Queen of Scots expert John Guy, who wrote the 2004 biography of Mary Queen of Scots, said it is the most important find about Mary in a century.
He said: “This discovery is a literary and historical sensation. Awesome! This is the most important new find on Mary Queen of Scots for 100 years.”
The authors suggest that other coded letters from Mary may be missing.