The mystery of Napoleon Bonaparte’s encrypted military letter remained unsolved for 217 years. Now AI engineer Carter Church, using the GPT-6 Astra model, deciphered the message in approximately six hours, reports UNN, citing Bild.
Details
According to media reports, the letter was sent in 1809 to General Auguste de Marmont. Napoleon instructed him to inform him of the strength and location of the French and allied forces, as well as to prepare for a march. At the time, the Austrian army was preparing to launch an offensive against France, while Marmont was stationed with his troops in Dalmatia, near present-day Croatia.
The original cipher key was lost. The text consisted of approximately 1,300 characters, with some symbols representing individual letters and others representing entire words. The AI first recognized the symbols in the scan, then matched them with a partially known cipher table and tested millions of variants until it obtained a meaningful French text.
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The deciphered message provides information about the location and strength of the French and allied armies. Marmont is urged not to allow "a few troops or a rabble" to intimidate him and to prepare for an offensive.
Marmont later indeed left Dalmatia with his army and joined Napoleon’s forces during the campaign against Austria. After the victory at Wagram, he was made a marshal.
According to the researcher, deciphering such a code would theoretically have been possible without AI, but it would have required an enormous amount of time. Over 217 years, cryptographers had still failed to fully reconstruct the letter’s contents.