01 The letter
| Shelfmark | BnF Français 23054 · Spanish numerical correspondence |
|---|---|
| Sender | Philip II / Archduke Albert |
| Recipient | Duke of Sessa / Philip II |
| Date | 31 March 1597 / 25 August 1596 |
| Language | Spanish |
| Report status | 3/3 pages transcribed in part; 3/3 pages deciphered in part |
| Ciphertext | 379 elements, 340 identified (89.7%) |
02 The key
174 codes; 2 values uncertain
- Key elsewhere
- Published Cp.39 reconstruction from a different volume, Français 15972 (Cryptiana).
03 The decipherment
f145r, full cipher lines 6–8
…que no se les puede dar, y assi sera de la prudencia de S.S. embiar al legado y a Juan Francisco las ordenes convenientes de los socorros que deven hazer en este año con el Emperador y el transilva[no].
Translation. …which cannot be given to them. Thus His Holiness should prudently send the legate and Juan Francisco the appropriate instructions for the assistance they are to provide this year with the Emperor and the Transylvanian [ruler].
04 Plaintext and other sources
Where a decipherment or clear copy already existed, as George Lasry gives it:
- Interlinear plaintext
- Historical interlinear plaintext on f145r, in this volume.
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 A. Image checked: https://gallica.bnf.fr/ark:/12148/btv1b9063548f/f272.item
- Folio matches the report: yes; cipher present: yes
- What we checked: f145r "El Rey / Duque de Sessa", Madrid 31 Mar 1597, signed Yo el Rey; codes "459 988 661 439 ... 437 ... 387" with his key: 661=se, 439=puede, 437=prudencia, 387=socorro, agreeing with the interlinear "que no se les puede dar ... de la prudencia de S.S. ... socorros" and his excerpt
- Verdict: confirmed (method read with known key, extent partial). The check is a sample, not a re-solution.
- Notes: Entry links only Cryptiana; the Gallica page is Fr. 23054 canvas f272. Full contemporary interlinear decipherment present and Cp.39 key published by Cryptiana - mostly an existing decipherment. 89.7% identified.
06 Notes and corrections
Gallica: Fr. 23054, canvas f272.
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. 61; his other items are listed on his contributor card.
- Fr. 23054, canvas f272 (the report links only Cryptiana)
- The working folder:
targets/sessa1597/(his entry as extracted from the report, our spot-check,profile.json).