For years, the researchers who visit National Library of France (BnF) went through a collection of coded letters. Someone wrongly dated the letters as originating in the 1520s and wrongly cataloged the contents as referring to Italy.
However, the letters were encrypted in a complex code. No one really knew what was in the letters or who wrote or received them.
An interdisciplinary research team studying Mary, Queen of Scots then suspected that the Queen had written the letters during her years in prison. After cracking the code, they translated 50,000 words written by the imprisoned queen. The team published their research in a special edition for February 2023 Cryptology. Theirs An insight sheds new light on the Queen of Scots’ darkest days.
What happened to Mary Queen of Scots?
Mary, Queen of Scots, began his life as queen and ended it as a prisoner. Born in 1544 James V of Scotland and Mary of Guise, her father died six days after her birth and she inherited the crown. The regents ruled on her behalf and she was sent to France at the age of six for her own protection.
The queen married Francis II — the Dauphin of France, soon to be King — at the age of 14. But he died two years later of illness and she returned to Scotland. Her years in Scotland were tumultuous. She married and had a son – James VI of Scotland and I of England – but political rivals contested her right to rule as queen.
Mary Queen of Scots and Lord Darnley (Credit: Original at Hardwick Hall, Derbyshire, National Trust/Public Domain, via Wikimedia Commons)
On February 10, 1567, Ann explosion in Kirk o’ Field house in Edinburgh killed Lord Darnley – Mary’s husband and James’s father. However, Lord Darnley and one of his servants were found outside the house with possible signs of strangulation, leading many to believe that was killed.
Mary became a suspect when she married the man accused of masterminding the attack – James Hepburn, Earl of Bothwell. However, there is speculation that Bothwell may have forced her to marry him.
Several Scottish lords known as Confederate Lords, imprisoned and forced Maria to abdicate the throne to her one-year-old son. She escaped from prison and fled to England to seek protection from her cousin, Queen Elizabeth I.
Queen Elizabeth, however, was not so hospitable. In the past, Mary had claimed her own right to the English throne, and Elizabeth had reason to worry that Mary could successfully unite the Catholics in the country against her. She orders Mary to be kept in the custody of the Earl of Shrewsbury, where she remains for the next 19 years.
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Mary, Queen of Scots Letters
During her years in captivity, Queen Mary wrote carefully coded letters to her allies. Her first languages were French and Scottish, and the letters found in the BnF collection were written in French.
Cryptologists identified, deciphered and translated about 50 letters. Most of the letters are addressed to the French ambassador Michel de Castelnaud, Sieur de la Mauvissière and were created between 1579 and 1584.
Cipher between Mary and Chateauneuf – selected parts (Credit: TNA SP52/22/22/ George Lasry, Norbert Biermann and Satoshi Tomokyo)
To crack the code, cryptologists began by using a computerized code-breaking program and then turned to linguistic and contextual analysis when necessary. They had more than 150,000 symbols to transcribe and used an algorithm called “hill-climbing” that allowed them to see if their decoding was correct.
Hill climbing
“Hill Climb” begins by selecting a random symbol. The computer makes a small change to the key and a decryption result is obtained. If the score is higher than before, they keep the key. If not, they try a new variation so the score keeps going up.
However, hill climbing can only take explorers so far. The algorithm encountered the characters that have a period placed below or to the side, and the team used contextual analysis to deal with these diacritics.
For example, the symbol “y.” it first appears after the phrase “sur l’arrivée prochaine”, meaning “for the impending arrival”. Usually “de” meaning (of) follows this phrase, but the researchers also knew that “deça” (here) was a possibility. They analyzed other uses and concluded that it most likely meant “de”.
Other symbols represent proper names, such as her son-in-law, the Duke of Anjou. The researchers likened the process of solving a giant crossword puzzle.
Read more: Neural Crossword Solver beats humans for first time
Cryptologists crack the code /
Mary, Queen of Scots Letters
After decoding and translating the letters, cryptologists analyzed and identified common themes in Mary’s letters.
Not surprisingly, Mary complained about her life in prison. And given that she was a widower Queen of France, she resented the indifference of the French authorities to her captivity. She felt abandoned.
Although she felt abandoned by the French, she warned the French ambassador not to trust Queen Elizabeth I or her representatives. She warned that the British would not be sincere with their negotiations and only sought to weaken France.
Mary named 120 people, many of whom she viewed as enemies. She disliked Francis Walsingham, Elizabeth’s spy, and provided evidence against Mary, including cipher letters, which he intercepted.
She also noted her dislike of the Earl of Leicester (a favorite of Queen Elizabeth I) and the Puritan faction. Given her awareness of the vast amount of enemies, it made sense that a common theme in the letters was her concern about maintaining her courier channels to carry the secret, coded letters to her allies.
Portrait of Elizabeth I, Queen of England, by Anonymous, c. 1550-99, (Credit: Everett Collection/Shutterstock)
The letters also include the mention of her dowry in France and her promise to financially reward her supporters. But by 1583 she felt that her attempts to negotiate with Elizabeth were futile. Mary hoped that she could return to the Scottish throne if she renounced all claims to the English crown. However, she understood that the Queen of England’s responses were only intended as a stalling tactic or to get political information out of her.
Mary was right that Elizabeth had no intention of helping her rival regain political power. Instead, Mary was arrested in 1586 and accused of plotting the assassination of Queen Elizabeth I. During the trial, other encrypted letters of Mary’s were used as evidence against her.
Mary was executed in February 1587 after 19 years as a prisoner. She was 44 years old. However, the captive queen lives on through her decoded letters more than 400 years after her death.