01 The letter
| Shelfmark | BnF Français 5581 · Letter from Mondesir |
|---|---|
| Sender | Writer in Mondesir, Isle de France (name not established) |
| Recipient | The writer’s wife |
| Date | 20 November 1769, with later additions |
| Language | French |
| Report status | 13/13 pages transcribed; 11/11 cipher pages deciphered |
| Ciphertext | 4,923 elements: 3,950 deciphered, 949 separator marks (?), 24 unidentified |
02 The key
24 mapped signs: 23 letter forms, 1 name; 2 personal signs unidentified. The key was recovered from the ciphertext alone.
03 The decipherment
f50v
même de son metier, aussi est on, on peu dire, ignorant presomptueux, entete comme un bas Breton qu’on est [?] se lai[s]se prevenir fortement souvent par le premier venu, entier dans ses idees qu'on a saisit promptement et mis à execution sans faire aucune reflexion ni consulter personne. Aussi fait on beaucoup de sottises et d'ordonnances dont on est obligé de revenir ou de laisser sans effets. [?] est vif jusque à l’emportement et aux exces…
Translation. Even in his own profession, he is, one may say, ignorant, presumptuous, and stubborn as a Breton. [?] lets himself be strongly prejudiced by the first person who comes along, clings to ideas hastily seized upon, and puts them into action without reflection or consulting anyone. This produces many foolish decisions and orders that have to be reversed or left without effect. [?] is impetuous, to the point of anger and excess.
f51r
la deffence sur l’agiotage des billets du Roy avec les piastres, sur lequel on a esté obligé de fermer les yeux comme sur la taxation des denrees de toute espece.
Translation. The ban on speculating in the king’s bills against piastres, on which they have been obliged to turn a blind eye, as with fixing the prices of provisions of every kind.
f56r, continuous paragraph, lines 3–6 — 56r
Et si après on veut maccorder des hommes et de largent et que jaye deux ans de paix pour me preparer a la guerre on verra la Différence du[c/n?] homme e un autre.
Translation. And if they then wish to give me men and money, and I have two years of peace to prepare for war, people will see the difference between [one?] man and another.
04 Our check
This result is George Lasry’s. This project did not re-solve the cipher: it checked one sample against the Gallica image and recorded what it found.
- Batch A. Image checked: https://gallica.bnf.fr/ark:/12148/btv1b9060477w/f53.item
- Folio matches the report: yes; cipher present: yes
- What we checked: f50r "Duplicata. De mondesir a l isle de france le 20 9bre 1769", "ma chere amie", clear French with pigpen-style cipher runs (e.g. after "pour ne pas"); sign shapes match his table (angle/box signs, dotted variants); a symbol-level decode of a run was not completed at this resolution
- Verdict: partly confirmed (method key recovered from ciphertext-only, extent partial). The check is a sample, not a re-solution.
- Notes: 3950 of 4923 elements deciphered, 949 counted as separators, 24 unidentified - complete by sense likely but his own figures are ambiguous. Clear text names Herman and M. de Bougainville; writer probably identifiable from the forge enterprise.
05 Sources
- George Lasry, with ChatGPT Astra 6 and Anthropic Opus 5.5, BnF cipher research, 10 October 2026 (sent to Daniel Bourdeau on 13 October 2026 for publication here), p. 35; his other items are listed on his contributor card.
- The working folder:
targets/mondesir1769/(his entry as extracted from the report, our spot-check,profile.json).