Louis XIV to Marquis de Feuquières, 9 December 1678 (BnF NAF 22738)

01 The letter

Shelfmark	BnF NAF 22738
Sender	Louis XIV
Recipient	Marquis de Feuquières
Date	9 December 1678
Language	French
Report status	4/4 pages transcribed; 4/4 pages deciphered in part
Ciphertext	1,920 elements, 1,169 identified (60.9%)

02 The key

67 codes: 18 letter signs, 49 in nomenclature

George Lasry’s reconstructed key table — George Lasry’s reconstruction of the key, as drawn in his report (p. 97). Image: George Lasry, BnF cipher research (10 Oct 2026); manuscript: Bibliothèque nationale de France, NAF 22738, Gallica btv1b10027843q view 294.

03 The decipherment

Manuscript lines with the cipher, from George Lasry’s report — The manuscript lines of the excerpt (f156r, lines 6–8), from the report, p. 98. Image: George Lasry, BnF cipher research (10 Oct 2026); manuscript: Bibliothèque nationale de France, NAF 22738, Gallica btv1b10027843q view 294.

f156r, lines 6–8

pouvoir reduire entierement les ennemis de la Suede par la force, que je crois important de profiter des dispositions où ils paroissent de s’accommoder avec cette Couronne,

Translation. to overcome Sweden’s enemies completely by force; I consider it important to take advantage of their apparent willingness to reach an accommodation with that Crown.

04 Plaintext and other sources

Where a decipherment or clear copy already existed, as George Lasry gives it:

Interlinear plaintext: Interlinear plaintext on ff156r–157v.
Plaintext in the margin or below: Marginal plaintext on f157r.

05 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 B. Image checked: https://openapi.bnf.fr/iiif/image/v3/ark:/12148/btv1b10027843q/f294/full/1600,/0/default.jpg
Folio matches the report: yes; cipher present: yes
What we checked: f156r lines 6-8: contemporary interlinear "pouvoir reduire entierement les Ennemis de la Suede par la force, que je crois important de profiter des dispositions ou ils paroissent de saccommoder avec cette Couronne" = his excerpt; docket "Louis XIV a M. le marquis de Feuquieres ... 9 xbre 1678"
Verdict: confirmed (method key recovered based on adjacent plaintext, extent partial). The check is a sample, not a re-solution.
Notes: Full interlinear decipherment on the pages, yet only 60.9% of number codes mapped in his key; the text itself is fully read from the interlinear.

06 Notes and corrections

A different item from targets/feuquieres.

07 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. 97; his other items are listed on his contributor card.
image checked in the spot-check
The working folder: targets/feuquieres1678/ (his entry as extracted from the report, our spot-check, profile.json).