• Megan Piorko & Sarah Lang

Cipher Treasure Hunt

While most scholars prefer not to be associated with a Robert Langdon type from Dan Brown’s popular novels or the treasure hunter Indiana Jones, investigating historical cipher codes can be a lot like a scavenger hunt at times. Still, retracing the origins of historical documents and the often very time-consuming detective work associated with interpreting these objects has a nerdy thrill.


The main difference between New York Times bestsellers and Hollywood blockbusters is the relatively slow pace of academic discovery. Historical academic adventures require tedious hours in the reading room and many long nights in front of the laptop. The final revelation is seldom instantaneous and usually achieved by collaboration between librarians, scholars, and cryptology experts, rather than one genius-type individual working alone. While the research aspect of scholarship would probably be considered boring by most people, it can result in fascinating new leads if one takes the time to dive into the material.

We are in the midst of an academic adventure to solve an historical cipher found in an early modern alchemical notebook which has, until now, been completely overlooked.

In this short blog post, we would like to take you on along with us on an alchemical quest. We are in the midst of an academic adventure to solve a historical cipher found in an early modern alchemical notebook which has, until now, been completely overlooked.


Our journey began in 2019 on a napkin in the back room of a dimly lit bar in Amsterdam. We had just finished the Society for the History of Alchemy and Chemistry 10th annual Postgraduate Workshop hosted by the Embassy of the Free Mind (opened by Dan Brown in 2017). Toward the end of the final round of drinks and goodbyes the discussion moved to a cipher discovered in a shared notebook of Paracelcian alchemical remedies written by a father and son team of 16th/17th century alchemical practitioners.


In the center of the notebook is a cipher table and two leaves of corresponding coded text, likely written by physician to Tsar Mikail I, Arthur Dee (1579-1651). After several failed attempts at solving the cipher on a crumpled napkin, we gave up for the evening. However, this mysterious cipher and code continued to occupy our minds.


Once we returned to our respective homes of Graz and Philadelphia, we began an international investigation in an attempt to crack the code. After testing several online decryption tools and even writing some code, it became clear that this cipher was actually much more complicated than it appears. Where historical ciphers are typically not created by experts and thus easy to solve with modern digital tools, this one was an anomaly.



This excerpt from the cipher shows repeating letters in certain words, which should be a clue to decoding it (or at the very least indicating which language it was originally written in), but in actuality they seem to be randomized beyond the simple cipher key provided. Some of the coded words begin with a double letter, which is not typical for Latin nor English, the two languages featured in the rest of the alchemical notebook. Additionally, frequency analysis did not show spikes which correspond to either Latin or English vowel distributions. This indicates that the cipher is not a simple monoalphabetic substitution. Our current assumption is that this is a polyalphabetic substitution cipher, similar to what is known as ‘Vigenère ciphers’. These types of ciphers require a password or passphrase to unlock them. We are currently on the hunt for the cipher’s secret code-word(s).


We have a few new leads from our research as fellows at the Science History Institute, and the historical context surrounding this cipher makes for excellent scholarly investigation, even without understanding the code. For instance, even without cracking this cipher we have learned that it was likely written during Arthur Dee’s time as Royal Physician to the Tsar in Moscow and also very close to the production of his manuscript, Arca Arcanorum, based on an entry in the notebook of the death of his wife, Isabella. If this is true, he was writing the cipher code around the same time as his claims of success with the Philosophers’ Stone.


Although we have not yet cracked the code, this alchemical cipher has brought us into contact with cryptology experts and historians of alchemy and chemistry around the world. We have been invited to present this cipher at events such as the Society for the History of Alchemy and Chemistry Postgraduate Workshop, a German medieval cipher network, and HistoCrypt in Amsterdam where our work will be published. We very much hope to understand the code better with the help of our newfound network of fellow cipher-lovers.


Megan Piorko and Sarah Lang are, respectively, Allington Postdoctoral Fellow and Hedegen Short-term Fellow at the Science History Institute in Philadelpia, USA. They have a forthcoming publication on their work on the cipher:

Lang, Sarah and Megan Piorko. “An alchemical cipher in a shared notebook of John and Arthur Dee (Sloane MS 1902).” In HistoCrypt 2021, forthcoming.


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