TOKYO, Oct 16 — Napoleon Bonaparte ordered a wartime message written in code, creating a puzzle that remained unsolved for more than 200 years — until artificial intelligence cracked it in a matter of hours.

AI is helping non-specialists unlock the secrets of historical sources, a development described as a “turning point” in a field previously dominated by scholars and dedicated hobbyists.

One new sleuth is Carter Church, a 27-year-old AI engineer who deciphered a 19th-century letter to one of Napoleon’s generals.

Without digital tools, the task could have taken weeks, but the latest model from ChatGPT-maker OpenAI broke the cipher in just six hours.