A reconstruction of how Mary, Queen of Scots’ last letter may have been secured shut using the spiral lock mechanism. Unlocking History Research Group Archive/MIT Libraries

Experts at the Massachusetts Institute of Technology and King’s College London have recently cracked the code of the spiral-locked letter of Mary, Queen of Scots. The results of their research are discussed in a paper published in the Electronic British Library Journal (2021): https://www.bl.uk/eblj/2021articles/article11.html. Here’s a note and a short video demonstrating the technique of the spiral-locked letters:

https://www.npr.org/2021/12/14/1062790520/mary-queen-of-scots-letterlocking-spiral-lock