Unknown writer → V. S. Ill.ma · homophonic substitution · c. 1527–1529 · key recovered from the adjacent plaintext

Siena nos. 13 and 16: the Pope, Bologna and Lautrec

A cipher letter and its clear copy filed apart in the same Sienese bundle; George Lasry rebuilt the key from the copy and deciphered the letter, which proposes to seize a castle as Lautrec seized Modena and Reggio.

Daniel Bourdeau · posted · updated

Method: key recovered based on adjacent plaintext · Extent: complete

Contributed by George Lasry (solution)

At a glanceKey from adjacent plaintext · complete

The letter
An unsigned letter to “V. S. Ill.ma” (a lord or ambassador), c. 1527–1529 from its content; ten lines of cipher with ten clear stretches.
Where
Archivio di Stato di Siena, Concistoro 2308, fasc. 2: the cipher is no. 13 (DECODE R4801), its clear copy no. 16 (DECODE R4804); both catalogued “1500–1599” with no status.
The cipher
Homophonic substitution, 37 signs, many shaped like numerals: one or two signs per letter, four signs for the doubled letters ll, gg, ss, cc, one null, no code words.
How it was deciphered
George Lasry transcribed the cipher and built an initial key in CTTS; Claude Fable 5.1 finalised the key and the transcription from the plaintext of no. 16 (17–18 October 2026).
What it says
The Pope’s agreements and his delay in coming to Bologna have left “qualche ruggine”; the writer would claim some castle, as Lautrec took Modena and Reggio, “perché al peggio non si ha sinon a rendere”.
Still open
The first word (baca?) and “sabbatte”; writer, addressee and exact date.
Credit
George Lasry, with CTTS and Claude Fable 5.1: transcription, key and reading, sent by email to Daniel Bourdeau on 17–18 October 2026. This page reports his result.

The project’s survey of the bundle (24 September 2026) had noticed that no. 16 is the clear text of no. 13 but did not rebuild the key; the other pieces of the bundle are described on its own page.

01The letter and its key

553 cipher symbols on ten lines, with clear stretches such as “saranno assai necessarie loro investigationi” and “et tutto si lassa i[n] la discretiss[im]a co[n]sideratione”. Most signs look like numerals (“23” is a, “19” and “111” are e, “11” is n), others like small letters and loops; a superscript circle or stroke belongs to several of them.

Key table of numeral-like signs under the letters A to Z with counts, four doubled-letter signs for CC, GG, LL, SS and one null
George Lasry’s key for no. 13, rebuilt with the clear copy no. 16: homophones under their letter, the doubled-letter signs and the null. Image: George Lasry, Concistoro 2308 fasc. 2 report (17 Oct 2026), signs cut from ASSi Concistoro 2308 fasc. 2 no. 13 (DECODE R4801).

02The decipherment

George Lasry’s reading, unchanged (cipher and clear text together; abbreviations expanded in brackets; the plaintext twin no. 16 settles the readings):

baca per che il papa in questi accordi con p[er] accordato et la tardanza de la ven[u]ta sua a Bologna pare che resti in qualche ruggine che saranno assai necessarie loro inuestigationi et adiuisi max[ime] ch[e] la maggior parte deli principali dela corte no[n] pare ch[e] ne parlino di lui sinon male non dando fede ala parente la fada bada et p[er]o haueremo giudicato al proposito i[n] questo dubbio et occasione spendare il tutto per abbassamento deli uicini et pretendendo in qual che castello far il fatto n[ost]ro come fe no[n] sabbatte quando passo Lutreche che a suo spete si piflio Modana et Reggio et quest per che al peggio non si ha sinon a rendere et tutto si lassa i[n] la discretiss[im]a co[n]sideratione di. V. S. Ill[ustrissi]ma

His translation: “baca(?) because the Pope, in these agreements, with per accordato and the delay of his coming to Bologna, it seems that some rust remains, so that their investigations and advice will be very necessary, especially as the greater part of the principal men of the court do not seem to speak of him except ill … and therefore we shall have judged it fitting, in this doubt and occasion, to spend everything for the abasement of the neighbours and, claiming some castle or other, to do our business as he did non sabbatte(?) when Lautrec passed, who at his own expense took Modena and Reggio; and this because at the worst there is nothing to do but give back; and all is left to the most discreet consideration of Your Most Illustrious Lordship.”

The papal journey to Bologna after agreements and Lautrec’s seizure of Modena and Reggio (1527) point to the years between the sack of Rome and Clement VII’s coming to Bologna in the autumn of 1529, 1527–1529. George Lasry marked the date as unverified in his report and confirmed 1527–1529 on 18 October 2026.

03What remains

Full texts

The transcription and the decryption of every document on this page, so that the reading can be used and checked. Short files are shown here; all are in the repository.

No. 13 (R4801), a letter on the Pope and Bologna, [1527-1529] (George Lasry)

To 'V. S. Ill.ma': the Pope's agreements and the delay of his coming to Bologna have left 'qualche ruggine'; the writer would spend everything to abase the neighbours and, claiming some castle, do as Lautrec did when he took Modena and Reggio, 'perché al peggio non si ha sinon a rendere'. Dated 1527-1530 from the content, unverified; no. 16 (R4804) is its clear copy. Decryption and translation are George Lasry's, verbatim from his report; his CTTS transcription is not in the repository.

Decryption

reading.txt

# No. 13 (R4801): George Lasry's decipherment, verbatim from his report of 17 Oct 2026 (pp. 35-36).
# Line breaks follow the PDF text layer, not the manuscript.

baca per che il papa in questi accordi con p[er] accordato et la tardanza de la ven[u]ta sua a Bologna pare
che resti in qualche ruggine che saranno assai necessarie loro inuestigationi et adiuisi max[ime] ch[e] la
maggior parte deli principali dela corte no[n] pare ch[e] ne parlino di lui sinon male non dando fede ala
parente la fada bada et p[er]o haueremo giudicato al proposito i[n] questo dubbio et occasione spendare il
tutto per abbassamento deli uicini et pretendendo in qual che castello far il fatto n[ost]ro come fe no[n]
sabbatte quando passo Lutreche che a suo spete si piflio Modana et Reggio et quest per che al peggio non
si ha sinon a rendere et tutto si lassa i[n] la discretiss[im]a co[n]sideratione di. V. S. Ill[ustrissi]ma
Decryption

lasry_report.md

# George Lasry's report: the section on this piece, verbatim

Source: George Lasry, "The cipher documents of Concistoro 2308, fasc. 2" (17 Oct 2026), consolidated report sent by email to Daniel Bourdeau; pp. 35-36. Text extracted from the PDF page by page with PyMuPDF, unchanged (line breaks as in the PDF text layer). The key figure and the manuscript crop are images in the PDF: `key_lasry.jpg` here, `docs/siena13_key.jpg` and `docs/siena13_lead.jpg`. The report has no separate appendix text for this piece beyond what is below (the full decipherment and translation are in the section).

## Entry in the report's contents (p. 2)

```
H. Pieces with an interlinear or separate plaintext
• No. 9 = R4798
 
  — Castiglione and the King of Aragon, 1440s–50s, 53 symbols — solved from the 
interlinear plaintext by Lasry with CTTS and Claude (15–17 October 2026)
• Nos. 13 and 16 = R4801
 
  — 553 symbols — plaintext on another folio in the collection (R4804) — solved 
with CTTS and Claude Fable 5.1 from that plaintext (17–18 October 2026)
```

## The section

```
[report page 35]

No. 13 (R4801): letter to V. S. Ill.ma on the Pope and Bologna, deciphered 
with its plaintext twin no. 16 (R4804)
Status. Solved. Transcription and initial key with CTTS (the author); Claude Fable 5.1 finalised the key and the
transcription from the given plaintext of no. 16 (R4804). 17–18 October 2026.
References
• Archivio di Stato di Siena, Concistoro 2308, fasc. 2 (Lettere in cifra), nos. 13 and 16
• DECODE records R4801 (Concistoro_2308_55) and R4804 (Concistoro_2308_58), 
https://de-crypt.org/decrypt-web/RecordsView/4801
Ciphertext
553 cipher symbols on 10 lines with ten clear stretches; the plaintext is no. 16.
Key
37 distinct signs. Homophonic substitution: one or two signs per letter, four doubled-letter signs (ll, gg, ss,
cc), one null; no word codes.
Signs as cut from the manuscript, with their number of occurrences; homophones stand under their letter.
Decryption
Cipher in bold, clear text plain; abbreviations expanded in brackets; the plaintext twin no. 16 settles the readings.
baca per che il papa in questi accordi con p[er] accordato et la tardanza de la ven[u]ta sua a Bologna pare
che resti in qualche ruggine che saranno assai necessarie loro inuestigationi et adiuisi max[ime] ch[e] la
maggior parte deli principali dela corte no[n] pare ch[e] ne parlino di lui sinon male non dando fede ala
parente la fada bada et p[er]o haueremo giudicato al proposito i[n] questo dubbio et occasione spendare il
tutto per abbassamento deli uicini et pretendendo in qual che castello far il fatto n[ost]ro come fe no[n]
sabbatte quando passo Lutreche che a suo spete si piflio Modana et Reggio et quest per che al peggio non
si ha sinon a rendere et tutto si lassa i[n] la discretiss[im]a co[n]sideratione di. V. S. Ill[ustrissi]ma


[report page 36]

baca(?) because the Pope, in these agreements, with per accordato and the delay of his coming to
Bologna, it seems that some rust remains, so that their investigations and advice will be very necessary,
especially as the greater part of the principal men of the court do not seem to speak of him except ill, giving
no credence to the apparent … bada and therefore we shall have judged it fitting, in this doubt and occasion,
to spend everything for the abasement of the neighbours and, claiming some castle or other, to do our
business as he did non sabbatte(?) when Lautrec passed, who at his own expense took Modena and
Reggio; and this because at the worst there is nothing to do but give back; and all is left to the most
discreet consideration of Your Most Illustrious Lordship.
Contents
From: unknown
To: V. S. Ill.ma (a lord or ambassador)
Place: unknown
Date: 16th century — the Pope’s coming to Bologna and Lautrec’s taking of Modena and Reggio (1527) point
to 1527–1530; unverified
Written to a Most Illustrious Lordship: the Pope’s agreements and the delay of his coming to Bologna have
left some ill feeling; the correspondent’s investigations and advice will be much needed, since most of the
leading men of the court speak ill of him; the writer therefore judges it right, in this doubt, to spend
everything to abase the neighbours and, by claiming some castle, to do as Lautrec did when he took Modena
and Reggio at his own cost, since at worst they would only have to be given back; all is left to the Lordship’s
discretion.
Historical context and dating
The clear text sets the letter at the time of a papal journey to Bologna after agreements, with Lautrec’s
seizure of Modena and Reggio as the recent example (1527): the years 1527–1530, between the sack of
Rome and the Bologna meeting of Clement VII and Charles V, fit; writer and addressee are not named and
the fascicle gives no date. Unverified.
Open points. Writer, addressee and exact date; the first word (baca?) and the word “sabbatte”.
```
Translation

translation.txt

# No. 13 (R4801): George Lasry's translation, verbatim from his report of 17 Oct 2026 (pp. 35-36).
# Line breaks follow the PDF text layer, not the manuscript.

baca(?) because the Pope, in these agreements, with per accordato and the delay of his coming to
Bologna, it seems that some rust remains, so that their investigations and advice will be very necessary,
especially as the greater part of the principal men of the court do not seem to speak of him except ill, giving
no credence to the apparent … bada and therefore we shall have judged it fitting, in this doubt and occasion,
to spend everything for the abasement of the neighbours and, claiming some castle or other, to do our
business as he did non sabbatte(?) when Lautrec passed, who at his own expense took Modena and
Reggio; and this because at the worst there is nothing to do but give back; and all is left to the most
discreet consideration of Your Most Illustrious Lordship.

Key: key_lasry.jpg, key.md

04Sources

Manuscript rights: Archivio di Stato di Siena.

Report text, key figure and profile: targets/siena13/.