Codebreakers have cracked the secret messages in Mary Queen of Scots’ letters she wrote while imprisoned more than 430 years ago. The coded letters were written while Mary was in prison thanks to her cousin Queen Elizabeth I, and were subsequently believed to have been lost for centuries until found in a French library.
The research team decoded the letters using a combination of computerised and manual techniques, and unveiled the challenges Mary faced in maintaining her links to the world outside her cell, how the letters were delivered and by whom. A key theme in the correspondence included complaints about the deposed Queen’s poor health and her conditions in captivity, as well as her negotiations with her cousin for her release, which she found was not conducted in good faith.
The letters also showed her distrust in Queen Elizabeth’s spymaster Sir Francis Walsingham, and her animosity for her cousin’s favourite, The Earl of Leicester Robert Dudley. The decoders also found Mary expressing distress upon the abduction of her son James, who would become King James I of England, in August 1582 and show her feeling of abandonment by France.
How were Mary Queen of Scots letters found?
The letters were discovered accidentally when George Lasry, a cryptographer and computer scientist, Norbert Biermann, a pianist and music professor, and Satoshi Tomokiyo, a patents expert and physicist, were searching the online archives of enciphered documents at France’s national library, Bibliothèque nationale de France’s (BnF). Who had authored the letters were only discovered after solving her highly sophisticated cipher system.
Around 50 new scripts previously unknown to historians were discovered using a 57 letter decipherment work that had been published in the journal Cryptologia on the 436th anniversary of Queen Mary’s execution at Fotheringhay Castle in Northamptonshire when the queen was 44 years old. Written between 1578 and 1584, the correspondence reveals new insights into her captivity.
Most of the letters were addressed to the French ambassador to England at the time, Michel de Castelnau de Mauvissière. The ambassador was a supporter of Catholic Queen Mary, who was in custody of the Earl of Shrewsbury when writing.
What do the letters reveal?
Lead author of the research, Dr Lasry, said: “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.
“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. The letters we have deciphered...are most likely part of this lost secret correspondence.”
Who was Mary Queen of Scots?
Mary Queen of Scots is one of the most famous figures of 16th century Britain, and was first in line to become Queen after her cousin Queen Elizabeth. A Catholic, Mary was imprisoned for 19 years by Elizabeth, who saw her as a threat to her reign and to Anglican England.
At age 44, Mary was executed for her alleged involvement in a plot to assassinate the Queen. But during her years in imprisonment, Mary communicated with her supporters and allies via extensive efforts to recruit messengers and maintain secrecy.
Queen Mary’s correspondence with the French ambassador is well known by historians as well as by the English government at the time. But the new discoveries show that it began as early as May 1578 and kept going until at least mid-1584.
Listed in the BnF catalogue as letters concerning Italian matters from the first half of the 16th century, the researchers quickly realised upon deciphering the correspondence that they were in French and had nothing to do with Italy. Dr Lasry and his team discovered verbs and adverbs in feminine form along with mentions of captivity and the name Walsingsham, leading to suspicions the letters were penned by Mary.
That the letters were indeed from Mary was confirmed by comparing them with plaintext letters in Walsingham’s papers in the British Library. After the discovery, a search for similar correspondence in the BnF collections unearthed 57 letters using the same cipher.