Carter Church: I used GPT-6 Astra to break an unsolved cipher to one of Napoleon's generals
Carter Church @CarterWChurch · x · 2026-09-30 · ★★★ · archived
First-hand account of the Marmont cipher break (~4.2M views on Oct 1).
Summary
A 6-post thread. Church says the impressive part was not the codebreaking itself: Astra ran the whole multimodal workflow (transcription, solver, verification) in about 6 hours from one image and a goal. It links to his writeup at carter.church.
Archived text
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.
Media: https://pbs.twimg.com/media/HTcOvxtWAAAcdIO.png
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Archived 2026-10-01 via syndication.
Related events
- GPT-6 Astra breaks an unsolved 1809 Napoleonic cipher letter to Marshal Marmont from a single scan 2026-09-18
All posts · id: 2026-09-30-carterwchurch-astra-marmont-cipher