AI Decodes Encrypted 1809 Napoleonic Letter
An artificial intelligence model decrypted a 200-year-old wartime cipher in just six hours.
Updated on Oct. 16, 2026 in Artificial Intelligence
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Artificial intelligence tools have successfully decoded a secret letter written to a Napoleonic general in 1809. Carter Church used the GPT-6 Astra model to translate the text, which details French and allied troop positions.
Why it matters
The successful decryption demonstrates how AI can process complex data volumes and historical ciphers that have eluded human experts for centuries. Traditional methods for these tasks remain time-intensive and labor-heavy, highlighting a shift toward automated historical research.
The AI process completed the decryption in six hours after remaining unsolved for 200 years. Modern projects are now achieving character recognition rates between 88 and 94 percent on complex medieval archives.
The players
Carter Church
He is the researcher who utilized the GPT-6 Astra model to successfully decrypt the historical letter.
Satoshi Tomokiyo
He is a researcher based in Tokyo who maintains an online repository of unsolved ciphers known as Cryptiana.
The details
Carter Church spent his evenings reviewing the 1809 letter before leveraging an AI model to break the encrypted troop positioning data. This success follows a broader trend where AI is being applied to transcribe 10 million pages of Hebrew manuscripts and 14,600 Latin administrative pages.
Timeline
79 AD: The Vesuvius eruption carbonized the Herculaneum Papyri.
1809: Napoleon ordered the writing of the coded letter.
June 2026: Researchers performed the first virtual unrolling of an ancient scroll.
Mid-September 2026: Most ciphers listed on Cryptiana were solved using AI.
October 2026: Satoshi Tomokiyo, a cipher researcher, was documented in Tokyo.
The Tech Race
This development follows the precedent set by the Herculaneum Papyri virtual unrolling project in using advanced computing to recover lost history. It signals a move away from manual archival work toward AI-driven data extraction.
The deployment of these AI tools speeds up the accessibility of historical records previously locked away in archives. Users can expect more rapid transcription and translation of diverse global historical documents as these systems mature.
The takeaway
Artificial intelligence is proving to be a powerful tool for unlocking historical data that was previously considered inaccessible due to labor constraints. The shift suggests that future breakthroughs in linguistics and archival studies will rely heavily on high-speed pattern recognition systems.
Further reading
Learn more about the latest developments in Artificial Intelligence research.
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