The Decrypted History of Mary, Queen of Scots

Historian Jade Scott draws on hundreds of encrypted letters to paint a vivid portrait of one of history’s most compelling figures in Captive Queen: The Decrypted History of Mary, Queen of Scots.

For almost two decades before her execution at Fotheringhay Castle in 1587, Mary, Queen of Scots was a prisoner. From her chambers, she wrote countless letters, many encrypted using complex ciphers to prevent her communications from being intercepted. In this way, she used language to exert her will and her influence, even while incarcerated.

More than four hundred years after her death, 57 of these encoded letters were unearthed in a French archive and decoded—a discovery described by experts as a “literary and historical sensation” and the most important new find on Mary for more than a century.

The excerpt below comes from the book’s Introduction.

Mary, Queen of Scots spent eighteen years as a captive in England, from 16 May 1568 until her execution on 8 February 1587. She was moved between properties and passed between jailers, kept to the northern and midland reaches of the kingdom, never coming any closer to the English court than Fotheringhay Castle in Northamptonshire. She rarely had any say in where she would be accommodated, though on occasion her dogged persistence succeeded in gaining temporary reliefbeing removed from her most hated prison at Tutbury Castle in Staffordshire to more comfortable properties nearby or travelling to take the mineral waters at the spa in Buxton. By reconstructing her movements during these captive years, we can watch the ever-changing periods of acute crisis and tedious inaction that characterized her life. As plots were hatched—and foiled— we see Mary being shunted to more remote locations, far from any potential rescue attempt. We share in her frustrations as she was left to linger for weeks and months on end, in gloriously gilded cages. And in her last captive years, as both Mary and her enemies determined to bring things to an end one way or another, we watch as she was brought south, much farther than she had been permitted before. Brought suddenly south, to her end.

During her captivity in England, letters were a lifeline for Mary. She wrote endlessly to family and friends in France, to supporters in Spain, to allies in Scotland and to her adversaries across England. She pleaded to be allowed to discuss her situation in person. She railed against the conditions of her captivity. She cajoled and flattered and threatened. Letters became her weapons, her armour, her battle strategy. Sometimes she would pen letters in her own hand, filling pages and pages with her neat handwriting, squeezing words into the margins of the paper. At other times, she would dictate letters to her secretaries, who would copy down her words, or else she would leave notes for them to polish into fully formed texts, which she would cast an eye over before signing her name at the bottom of the page. A speaker of several languages, her letters were multilingual—she wrote in French, English, Scots, Latin and Italian.

Several thousand letters to and from Mary, Queen of Scots survive, scattered in archives and collections across the world. They enthrall and entice us. When the last letter Mary ever wrote was put on public display at the National Museum of Scotland in Edinburgh in February 2017 to commemorate the anniversary of her death, the crowds were so big that additional viewings had to be organized. We thrill to see her signature there on the page: a letter of hers with a postscript in her own hand came to market in 2022 and sold for £32,500, more than double the asking price. Mary’s letters were prized during her lifetime too, though for different reasons. Her letters were gathered as evidence against her at her final trial in 1586, held up as proof of her involvement in plots that sought to depose and even assassinate Queen Elizabeth I of England. Her signature was the golden prize—if Mary had signed a letter with her own hand, then she was understood to have authorized the contents within. So, while she was able to send and receive letters throughout her years as a captive in England, her correspondence was always subject to surveillance by English courtiers. William Cecil, Lord Burghley, the Lord High Treasurer of England and Elizabeth’s closest advisor, and Sir Francis Walsingham, principal secretary and chief spymaster, managed this surveillance network, regularly intercepting Mary’s letters. Sometimes letters would be held up en route, with a copy made and the original letter sent on with a replica wax seal attached. The recipient might never suspect anything untoward, so expert were these intelligencers. As Mary would discover at her final trial in 1586, letters of hers that were intercepted could also be altered by these agents, making it appear that she had given instructions that she herself would later deny.

As her captivity went on, with diminishing hopes of a diplomatic agreement in her favour, and ever more dramatic schemes drafted in response, Mary’s access to the outside world was incrementally curtailed. Diplomatic correspondence and letters regarding her finances were still transmitted using official postal channels that were supervised by Sir Francis Walsingham. Mary referred to this official route as “the ordinary way” or more archly as “Walsingham’s way” in recognition of his close monitoring. So intense was Walsingham’s surveillance that Sir Ralph Sadler, ambassador to Scotland and respected courtier during Elizabeth’s reign, was once forced to explain what some odd-looking marks were on the back of a letter he was sending on from Sheffield Castle, where he had been guarding Mary for a while; in a postscript, he clarified that they were not hidden messages but simply pen marks where his young secretary had scribbled on the page before scraping them away when he realized his mistake.

Mary was well aware that her letters were read by third parties, which was problematic when she wanted to convey information of a more sensitive nature. If she wished to correspond with supporters without Walsingham’s spies poring over the contents of her letters, she needed a disguise. She began to compose more and more letters in cipher, using coded symbols to hide names, places and dates. Eventually entire letters were written in cipher, but we are unsure whether Mary actually penned them in her own hand—naturally, she did not sign ciphered letters. Usually, Claude Nau, her French secretary, would write letters in French, while those that were to be translated into Scots or English would be drawn up by her Scottish secretary Gilbert Curle. Each would usually then transcribe the letter text using ciphers, with multiple levels of obfuscation: individual people and places, as well as dates, would be given a unique symbol; letters of the alphabet would be disguised; red herrings would be added; words or letters would be doubled unnecessarily; and phrases would be added indicating to the reader that the previous word was to be deleted. The ciphers themselves were a mix of graphical symbols and alphabetic letters drawn from Greek and Arabic.

Codes and symbols were routinely used in the period to disguise information and could range in complexity. Mary relied upon multiple different ciphers in her letters: more than seventy different combinations survive, with specific versions brought into action depending on the person she was communicating with. She also made sure to keep changing the ciphers, either to avoid unwanted readers potentially breaking them, or because she realized that examples had been intercepted. Coded correspondence relied on both parties having access to a key, which would allow the hidden text to be revealed. If keys were discovered, then the cipher had to be adapted; her principal secretary back in Scotland and lead supporter during her English captivity, William Maitland of Lethington, wrote to her attendant and friend Agnes Fleming, Lady Livingston, warning Mary against using their usual code when he realized it had been lost after a loyal messenger was arrested and was now “known to their adversaries.” Mary’s letters are therefore peppered with references to “alphabets” and at various moments of crisis—usually when a new plot was being planned or a conspirator had been taken by her enemies—she would be forced to change the codes used.

About the author

Dr. Jade Scott is a historian specializing in Mary, Queen of Scots and an expert on her letters. She is an affiliate in History at the University of Glasgow, an associate fellow of the Royal Historical Society and Secretary of the Scottish History Society, researching early modern Scottish women and their correspondence. She lives in Stirling with her husband and two St Bernards.