Primary Contributors:
Emma Grummitt, with EMLO and the Cultures of Knowledge research project
Introduction
In the early modern period, ciphered communication was an integral part of the correspondence networks of international diplomacy, political discord, and espionage. Yet despite its extensive use throughout the period, the particulars of ciphered communication have often been overlooked in traditional archival practices. Primarily, the focus has been on the content of these documents, rather than how the information was disseminated. This collection of ciphered letters in EMLO aims to shed new light on early modern ciphers in all of their multitudinous varieties by examining the morphological features of the ciphers themselves. It is hoped that it will be possible to create an ontology of cipher categorization which may be used to frame archival descriptions in a structured manner and to enable discussions between scholars and across projects as well as across thematic fields.
The visualization below outlines the different features of cryptographic correspondence and it can be used as a guide for contributors to this collection of cipher letters. To categorize the cipher in a document, the hierarchal structure charted in the diagram can be employed to narrow down the field of reference and accurately define the code used. The visualization has been colour-coded to encourage the user to describe a cipher step by step, resulting in a definition that can be entered in a searchable and categorized format in the ‘General Notes’ field of the letter’s record in EMLO.
Note for users and future contributors: each branch of the tree diagram is collapsible. Please start from the ‘Encrypted Text’ field and expand each branch to narrow down the frame of reference for the cipher in your document. Each field has a note attached defining the terminology and providing examples to aid categorization. At present, this project is a work in progress, so if you would like to suggest more fields or examples be added to this visualization, please be in touch.
Partners and Additional Contributors
This fledgling project was initiated and developed by Emma Grummitt, a student on the MSc in Digital Scholarship course, whilst on a practical placement with Early Modern Letters Online [EMLO]. During Trinity term 2025, Emma worked with the staff at EMLO in the Faculty of History. The placement was facilitated by the MSc in Digital Scholarship at the University of Oxford.
Contents
To date, the correspondence catalogues in this collection include:
- The Cipher Books of John Wallis (1653)
- Excerpts from the Cipher Book of John Wallis, Bodleian Library, MS. Eng. misc. c. 382 (1690–91) [starter catalogue]
- The Correspondence of Aphra Behn (1666)
- Excerpts from the Carte Collection (1660/1) [starter catalogue]
Scope of Catalogue
This collection marks the beginning of what it is hoped will become a thematic cluster of cipher letters in EMLO. If you are a student either in search of a topic or interested in working with early modern cipher correspondence, we invite you to be in touch to discuss how you might engage with this topic. Alternatively, should you be a more senior scholar—or a member of a research project team in the process of drafting an application for funding—and ciphered correspondence is integral to your work, we should be delighted to discuss the possibilities of working together.
Further resources
Selected Bibliography
Akkerman, N., ‘Enigmatic Cultures of Cryptography’, in J. Daybell and A. Gordon, eds, Cultures of Correspondence in the Early Modern Period (Philadelphia: University of Pennsylvania Press, 2016), pp. 209–28.
Akkerman, N., Invisible Agents: Women and Espionage in Seventeenth-Century Britain (Oxford: Oxford University Press, 2018).
Akkerman, N. and Langman, P., Spycraft: Tricks and Tools of the Dangerous Trade from Elizabeth I to the Restoration (New Haven: Yale University Press, 2024).
Daybell, J. and Gordon, A., eds, Cultures of Correspondence in the Early Modern Period (Philadelphia: University of Pennsylvania Press, 2016).
Ellison, K., ‘Millions and Millions of Distinct Orders: Multimodality in Seventeenth-Century Cryptography Manuals’, Book History, 14 (2011) pp. 1–24.
Ellison, K., Secret Writing in the Long Eighteenth Century: Theories and Practices of Cryptology (Cambridge: Cambridge University Press, 2022).
Kahn, D., The Codebreakers: The Story of Secret Writing (New York: Scribner, 1996).
Kim, S. and Ellison, K., eds, A Material History of Medieval and Early Modern Ciphers: Cryptography and the History of Literature (Abingdon: Routledge, 2017).
Pratt, F., Secret and Urgent: The Story of Codes and Ciphers (London: Robert Hale Limited, 1939).
Tomokiyo, S., Cryptiana: Articles on Historical Cryptography (Cryptiana website, n.d.) [accessed 12 June 2025].
Launch all letters in the ‘Early Modern Cipher Correspondence’ Collection