Secret Napoleon Letter Deciphered Using Neural Network After 217 Years
Artificial intelligence helped decode a secret military dispatch from Napoleon Bonaparte to General Auguste de Marmont 217 years after it was sent, announced Carter Church, a specialist at SentinelOne, on social media platform X.
A modern language model, GPT-6 Astra, succeeded in reconstructing the encrypted 19th-century text in just six hours. Such technologies provide historians with the opportunity to swiftly study previously inaccessible archives without years of manual researcher work.
The historical message is dated 1809 and was delivered to the French military commander in Dalmatia via the emperor’s stepson, Eugène de Beauharnais. The dispatch contained information on coordinating army corps on the eve of military operations against Austria. Thanks to these instructions, the recipient timely combined his units with the main forces and distinguished himself in the Battle of Wagram, after which he was promoted to marshal.
The original cipher key was not preserved, making it impossible to read the manuscript for over two centuries. The document itself consisted of approximately 1,300 encoded elements and included 155 diverse symbols, among which were digits, letters, and special graphic characters.
To solve the task, the neural network used the simulated annealing method, relying on just 33 pre-deciphered symbols. All symbol chains generated by the algorithm were automatically compared with French texts from that period and surviving manuscripts of the marshal himself.
Among the deciphered lines was a warning about the imminent fall of the Austrian state under the onslaught of Napoleon’s corps. The text stated: "Austria is being attacked simultaneously from all sides. Consequently, it is swiftly moving toward its demise."