Nicodemo Tranchedini to Francesco Sforza, 28 June 1452

01 The letter

02 The key

55 symbols: 23 letter forms, 32 in nomenclature

Key elsewhere

Domnina (2018), Figure 5: reconstructed Tranchedini key from the 1449 letter and a 1454 decipherment. Matching values are checked against the 1452 manuscript.

03 The decipherment

The report gives no excerpt for this item.

04 Plaintext and other sources

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

Plaintext in another folio of the same volume

Literal historical decipherment on f88r–v, immediately before the cipher on f89r (PDF84–85).

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/btv1b100387843/f83.item
• Folio matches the report: yes; cipher present: yes
• What we checked: f89r "Post data ... Signore" cipher postscript dated 28 Jun 1452, signed Nicodemus; facing f88v carries the contemporary decipherment (clear: "vescovo de Novara ... la V. Ill. hauria ben facto ... paragonata ... Certificandone Signore"), which matches the clear islands on f89r and his contents; no symbol-level decode of a run done
• Verdict: partly confirmed (method read from existing decipherment, extent partial). The check is a sample, not a re-solution.
• Notes: A literal 15th-c. decipherment sits on f88r-v next to the cipher, and the key is Domnina 2018s reconstruction, so little is new beyond alignment. Transcription incomplete; status Partly deciphered.

06 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. 49; his other items are listed on his contributor card.
• The working folder: targets/tranchedini1452/ (his entry as extracted from the report, our spot-check, profile.json).