Napoleon's code is cracked after 217 years: Scientist uses AI to read a mysterious letter written by the Emperor in 1809

SentinelOne cybersecurity engineer Carter Church used OpenAI's GPT-6 Astra to decode a 217-year-old coded letter from Napoleon's stepson Eugene to General Auguste de Marmont, written in 1809, Church announced on X. Church said Astra completed the entire multi-modal workflow in about 6 hours from a single image and goal, cutting a 1,202 by 1,836 plate into rows, reading the signs, and determining which of 175 hand-drawn marks were the same sign written twice. The deciphered text details the disposition of French and allied armies, including 40,000 Bavarians under the Duke of Danzig at Munich and Passau and 80,000 French troops under the Duke of Auerstaedt at Bayreuth.

A mysterious letter written by Napoleon Bonaparte has been decoded for the first time in more than 200 years. The letter was sent to Auguste de Marmont by Napoleon's stepson, Eugene, the Viceroy of Italy https://www.dailymail.com/news/italy/index.html , in 1809. The first line is written in French, but the 24 lines that follow consist of two-digit numbers, stray letters, and invented symbols. While the letter would have originally come with a key, this has long been lost – meaning the contents have been a mystery. Now, Carter Church https://carter.church/writeups/the-letter-to-marmont/ war , an engineer at cybersecurity company SentinelOne, has cracked the code, using AI https://www.dailymail.com/sciencetech/ai/index.html . 'I used GPT–6 Astra to break an unsolved cipher to one of Napoleon's generals that had gone unread for 217 years. What makes this impressive isn't actually the codebreaking, but that Astra completed the entire multi–modal workflow in ~6 hours from a single image and goal,' he explained on X. A mysterious letter written by Napoleon Bonaparte has been decoded for the first time in more than 200 years Napoleon's decoded message Those letters contained the orders and instructions which His Majesty charged me to give you. I hasten today to acquaint you with the disposition of French and allied armies. The Duke of Danzig, at the head of forty thousand Bavarians, occupies Munich and Passau. Prince Poniatowski, at the head of thirty thousand Poles, is camped on the Vistula, threatening Cracow. The Prince of Ponte-Corvo commands the Saxon army, camped in front of Dresden, and the Duke of Auerstaedt occupies Bayreuth with eighty thousand French troops. The Duke of Rivoli commands sixty thousand men quartered at Ulm and Donauwörth. General Oudinot, with the elite corps comprising forty thousand men, is at Augsburg and along the Lech. The Russians are marching against Austria, and the army of Friuli today numbers eighty thousand men. Add the Dalmatian corps, without counting the reserves being organized everywhere in the rear, and you see that Austria will be attacked at once on every side. She is consequently hastening toward her ruin. When you receive the order to march, you must not allow yourself to be intimidated by a few troops or a gathering of rabble. I continue to await news from you with impatience. The Austrians are still at Laybach, Klagenfurth, Villach and Salzburg, and appear to threaten the Tyrol by way of Lintz. Yet one would think that they are considering sending troops into Galicia to oppose the Russians. These dispositions would suggest that their campaign plan has been upset before war has even been declared. There is, however, still nothing definite. The militia have been called into active service, and although efforts have been made to excite people, it has not yet been proved that these levies will provide much reinforcement for the army. On March 16, 1809, Napoleon wrote from Paris to his stepson, Eugene, asking him to send a letter to Auguste de Marmont – a friend of the Emperor, whose troops were positioned in Dalmatia, on the far side of the Adriatic. With Austrian territory sat between them and every other French army, Marmont would have been isolated if war came. The first line is in French, and reads: 'Vous avez dû recevoir, Monsieur le Général Marmont, mes lettres des 8, 14 et 20 courant.' This translates to: 'You must have received, General Marmont, my letters of the 8th, 14th, and 20th of this month.' However, with the rest of the letter written in code, its meaning has been unclear. To crack it, Mr Church turned to GPT-6 Astra – an AI model created by OpenAI. Over six hours, the bot was able to decipher the message. 'Astra cut the 1,202 by 1,836 plate into rows, read the signs, decided which of 175 hand–drawn marks were the same sign written twice, and only then began breaking the cipher,' Mr Church explained in a blog post. The letter lays out the location of every other French and allied army, and urges Marmont to 'not be intimidated' by his isolated position. 'The Russians are marching against Austria, and the army of Friuli today numbers eighty thousand men,' it reads. 'Add the Dalmatian corps, without counting the reserves being organized everywhere in the rear, and you see that Austria will be attacked at once on every side. 'She is consequently hastening toward her ruin. 'When you receive the order to march, you must not allow yourself to be intimidated by a few troops or a gathering of rabble.' To crack it, Mr Church turned to GPT–6 Astra – an AI model created by OpenAI. Over six hours, the bot was able to decipher the message On 16 March 1809, Napoleon pictured in painting wrote from Paris to his stepson, Eugene, asking him to send a letter to Auguste de Marmont – a friend of the Emperor, whose troops were positioned in Dalmatia, on the far side of the Adriatic According to Mr Church, the cipher itself wasn't actually difficult to crack. However, he admits that it would have taken humans much longer than the AI, which was able to whizz through it in just six hours. He added: 'The cipher itself isn't difficult, and cryptographers could have cracked this easily given the time/energy. 'But, the work to transcribe, catalog, translate, then crack is involved and multi-disciplinary. 'Every field has an unsolved backlog of niche problems that specialists don't have the bandwidth to tackle. 'The takeaway here is that the people shortening those lists will increasingly be outsiders who were simply curious.' The start of the 19th century was a time of hostility between France and England, marked by a series of wars. Throughout this period, England feared a French invasion led by Napoleon. Ruth Mather explores the impact of this fear on literature and on everyday life. Following the brief and uneasy peace formalised in the Treaty of Amiens 1802 , Britain resumed war against Napoleonic France in May 1803. The start of the 19th century was a time of hostility between France and England, marked by a series of wars. Throughout this period, England feared a French invasion led by Napoleon left . The Duke of Wellington right defeated him in battle The return to war required the resumption of the mass enlistment of the previous ten years, especially as fears of a Napoleonic invasion once again intensified. The Corsican general Napoleon, soon to become emperor, had made no secret of his intentions of invading Britain, and in 1803 he massed his huge ‘Army of England’ on the shores of Calais, posing a visible threat to southern England. Hostilities were to continue until the British victory at the battle of Waterloo in 1815. The Battle of Waterloo was fought on 18 June that year between Napoleon’s French Army and a coalition led by the Duke of Wellington and Marshal Blücher. The decisive battle of its age, it concluded a war that had raged for 23 years, ended French attempts to dominate Europe, and destroyed Napoleon’s imperial power forever. The Battle of Waterloo was fought on 18 June that year between Napoleon’s French Army and a coalition led by the Duke of Wellington pictured on horseback and Marshal Blücher The French Emperor Napoleon Bonaparte had escaped from exile in March 1815 and returned to power. He decided to go on the offensive, hoping to win a quick victory that would tear apart the coalition of European armies formed against him. Two armies, the Prussians led by Field Marshal Gebhard von Blücher and an Anglo-Allied force under Field Marshal the Duke of Wellington, were gathering in the Netherlands. Together they outnumbered the French. Napoleon’s best chance of success was therefore to keep them apart and defeat each separately. Attempting to drive a wedge between his enemies, Napoleon crossed the River Sambre on June 15, entering what is now Belgium. The next day the main part of his army defeated the Prussians at Ligny and drove them into retreat, with losses of over 20,000 men. French casualties were only half that number. Pursued by Napoleon’s main force, Wellington fell back towards the village of Waterloo. Unknown to the French, the Prussians, although defeated, were still in good shape. They retreated northwards towards Wellington’s position and were able keep in contact with him. Emboldened by their promise of reinforcements, Wellington decided to stand and fight on June 18 until the Prussians could arrive. The victorious allies entered Paris on July 7. Napoleon surrendered to the British and was exiled to St Helena.