Mary Queen of Scots was far from the only person who was skilled in the art of 'letterlocking' – the technique became common throughout Europe during the Late Middle Ages (1250-1500) and Early Modern periods (1500-1815). Watch this and other letterlocking techniques on the Unlocking History Research Group's YouTube page.

Watch a reconstruction of how Mary did it: No wax or adhesive was required, but crucially, if someone tried to sneak a look, they would have to rip through the strip, so her brother-in-law would know the message had been intercepted. After poking the knife through the rectangle to make a hole, she then fed the strip through, looping it and tightening it a few times, creating a 'spiral lock'. Instead, Mary cut a thin strip from the paper margin, before folding up her message into a small rectangle. However, envelopes were not used in the 1500s – not least because paper was expensive – and there was no trustworthy postal service at the time. She didn't want her captors snooping – and particularly not her cousin Queen Elizabeth I.

'The Catholic faith and the assertion of my God-given right to the English crown are the two issues on which I am condemned.' With a sad acceptance of her fate, she asked him to take care of her affairs and pay her servants, wishing him 'good health and a long and happy life'.Īfter Mary had finished writing, she then began to fold up the letter to secure its contents. 'Tonight, after dinner, I have been advised of my sentence: I am to be executed like a criminal at eight in the morning,' she wrote. Late at night on 8 February 1587, an imprisoned Mary Queen of Scots composed her last ever letter to her brother-in-law.

Old letter envelope