At a glanceExisting decipherment · complete
- The document
- A slip of six lines, clear cursive mixed with cipher, under a clear memorandum on the same sheet. Unsigned and undated; c. 1440–41 from its contents.
- Where
- Archivio di Stato di Siena, Concistoro 2308, fasc. 2 “Lettere in cifra”, no. 8; DECODE R4797 (
Concistoro_2308_51), catalogued “1500–1599” with no status. - The cipher
- A simple substitution in letter-like signs: two signs for a, one for s and ss, one for u, v and b, and two name signs, for the Duke of Milan and the Venetians.
- How it was deciphered
- The memorandum’s last three paragraphs open with the slip’s clear words. Aligned letter for letter with them, the four cipher runs give one consistent key, which reads every sign.
- What it says
- The articles of a league between the Duke of Milan and the Marquis of Ferrara to make war on Venice; the Duke “aveva dato madonna Biancha a missere Leonello”, the Marquis’s son.
- Still open
- The memorandum’s first four paragraphs decipher a covering letter that is not on the sheet. Writer and date are not given.
- Credit
- The contemporary decipherer of the memorandum. George Lasry’s report of 17 October 2026 listed no. 8 as not yet deciphered and called a link with the memorandum “possible but speculative”. This page puts the alignment to him.
The other pieces of the Sienese cipher file are listed by key on the Concistoro 2308 index. Nos. 7, 19 and 21 are different ciphers, with their own pages; none fits this key.
01The sheet and the disagreement
The upper two thirds of the sheet are a clear memorandum in seven paragraphs. Each paragraph opens with an underlined catchword, and the words after it run on as plain prose: the layout of a decipherment, where the clear words of the ciphered letter are copied and the cipher after them is written out. The first four paragraphs (the Marquis of Ferrara “rimesso nel duca di Milano a fare guerra e pace”, “di papa Felice”, Niccolò Piccinino, Lucca) belong to a letter that is not on this sheet. The fifth opens “Nel polizolo dicto segue”, “in the said slip there follows”, and the last two catchwords, Anchora disse and antiveduto questo, are clear words on the slip below.
The project’s inventory of 24 September 2026 took no. 8 as deciphered at the time, from the memorandum’s contents alone. George Lasry’s report of 17 October 2026 lists it as not yet deciphered, “c. 400 symbols”, with no interlinear plaintext, a relation to the memorandum “possible but speculative”. On 18 October the slip was transcribed sign by sign and aligned with the memorandum, and the alignment settles the question.
02The alignment
The memorandum’s last three paragraphs, transcribed here (catchwords in italics):
Nel polizolo dicto segue: [modo?] leggiere e capitagli e legha fral duca di Milano el marchese di Ferrara a fare guerra a Viniziani e sua legha. Anchora disse el duca di Milano aveva dato la donna Biancha a misser Leonello figlolo del marchese. Antiveduto questo e no puo manchare che questo udrete grandissimi facti.
The slip’s four cipher runs, deciphered with the key rebuilt from that text (in the cipher’s own spelling; names in brackets are single signs):
- le|giere e chapitoli e legha fra [duca di Milano] el marchese di ferrara a fa|re
- [guerra, faint, in clear] [Viniziani] e sua legha
- [duca di Milano] aveva dato madonna Biancha a missere Leonello filgliuolo de marchese
- e non puo manchare che questo udirete grandissimi fatti
“… to read the articles of the league between the Duke of Milan and the Marquis of Ferrara, to make war on the Venetians and their league. He also said that the Duke of Milan had given Madonna Bianca to messer Leonello, the Marquis’s son. This being foreseen, it cannot fail that you will hear of very great deeds.”
The pattern words leave no room for chance: 5 9 T 9 5 is aveva (the shape ABCBA), F T W W 2 W 2 is ferrara, L T Z PHI T L L Z is leonello; the sign 7 is d in dato, madonna, di, de and udirete, and the two a signs never stand for anything else. The cipher and the memorandum differ only in spelling (chapitoli / capitagli, madonna / la donna, fatti / facti).
03The key
Twenty-one letter signs and two name signs, rebuilt from the alignment (sign names as in the transcription, targets/siena8/transcripts/no08.txt):
| Letter | Sign | Letter | Sign |
|---|---|---|---|
| a | z-shaped 2; hooked long s | m | I-beam |
| c | cross | n | stroke through a ring (φ) |
| d | 7 | o | 2 with a crossed foot |
| e | b with a crossed ascender (once a small raised 2) | p | hooked long stroke |
| f | o with a tail | q | hooked q (once) |
| g | η-like n | r | double ring |
| h | c | s, ss | long s joined to a crossed h |
| i | double long stroke | t | square |
| l | two rings joined | u, v, b | 9 |
| duca di Milano: double cross with four dots | Viniziani: box-like H | ||
The key is not among the filed keys compared by eye in September; the two keys of about 1440 that name the same persons, R4748 (“Cifra cum fratre Bernardino”) and R4749, have not yet been compared with it sign by sign.
04Date and context
The Marquis whose son is Leonello is Niccolò III d’Este, who died on 26 December 1441; “papa Felice” in the memorandum is the antipope Felix V, elected in November 1439; and Bianca Maria Visconti married Francesco Sforza in October 1441, so the report that her father had given her to Leonello belongs before that. The slip therefore dates from between November 1439 and October 1441 (most likely 1440–41). The writer, perhaps a Sienese envoy at Milan, is not named. This dating is proposed here, not written on the sheet.
05What remains
- The covering letter whose cipher passages the memorandum’s first four paragraphs decipher: not on this sheet and not among the DECODE photographs of the busta.
- Doubtful signs: a faint group in line 3, read as the clear word guerra; the end of the s sign in sua; the missing l of de(l); the p of puo; the q and u of questo, which occur only once. None changes the reading, which the memorandum gives.
- George Lasry’s confirmation of the alignment, and whether he counts c. 400 symbols for the whole slip with its clear words (the cipher signs alone are 166).
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.
Siena, Concistoro 2308 fasc. 2 no. 8 (DECODE R4797), c. 1440-41
A ciphered slip on the Milan-Ferrara league: the league between the Duke of Milan and the Marquis of Ferrara against the Venetians and their league, the Duke of Milan having given 'madonna Biancha' to messer Leonello, the Marquis's son, and 'grandissimi facti' to be expected. The clear memorandum on the same sheet (paragraphs 5-7) is its contemporary decipherment; the key rebuilt from the alignment reads all 166 signs.
Transcription
No. 8 (ASSi Concistoro 2308, fasc. 2) - DECODE R4797 (Concistoro_2308_51)
Image: IMG_R4797_I27940_P.jpg (portrait 2248x4000), one side. Upper two thirds: a clear memorandum
(the contemporary decipherment). Lower third: the ciphered slip (6 lines), pasted or bound below it.
Transcriber: Claude (claude-opus-5-5), 18 Oct 2026, from line crops at 3-4x native size.
THE SHEET
- The memorandum is written in paragraphs, each opening with an underlined catchword: "E disse di tutto
... dovessi scrivere", "di papa Felice", "Or tochiudendo(?) dicto etc.", "di buona voglia", "Nel
polizolo dicto segue" (= "in the said slip there follows"), "Anchora disse", "antiveduto questo".
The underlined words are the clear words of the ciphered text; the words after them are the
decipherment of the cipher that follows them. Paragraphs 1-4 belong to a letter that is not on this
sheet; the last three ("Nel polizolo dicto segue ...", "Anchora disse ...", "antiveduto questo ...")
are the decipherment of the slip below.
- The slip mixes clear cursive and cipher. Its clear words "Anchora disse" (L3) and "e stato antiveduto
questo" (L5) are the memorandum's last two catchwords.
SIGN LEGEND (codes used in no08.tok; values from the alignment with the memorandum)
T tall b-shaped sign with a cross-bar through the ascender e
z small raised 2 (once, L2) e (?)
2 z-shaped 2 with a long flat foot a
5 hooked long s (like a 5 / long-s with a flag) a
Z 2 whose foot is crossed by a descending stroke o
F small o with a tail stroke to the right (o-) f
W double ring (like omega / oo joined) r
L two rings joined by a horizontal stroke (o-o) l
+ plain cross c
c c h
Y double long stroke (ʃʃ / ꝑ-like double stem) i
P long stroke with a hooked top (single) p
Q square t
N eta-like n with a descender g
PHI upright stroke through a small ring (φ) n
7 7 d
9 9 u, v, b
I I-beam (capital I with serifs) m
S long s joined to a crossed h (ꞩh) s, ss
q hooked q-like sign (once, L6) q
U small ring sign after q (once, L6) u (?)
DM double cross with four dots (⁜) [duca di Milano] (2x)
VN box-like H sign (Ħ) [Viniziani] (1x)
Clear words in [ ]. "/" = the writer's stroke. "?" = doubtful sign.
TRANSCRIPTION (only the cipher and the clear words around it; L1 is clear up to the stroke)
L1 [Da poi ... chome s'era trovato modo /] L T
L2 N Y z W T T + c 5 P Y Q Z L Y T L T N c 5 F W 2 DM T L I 2 W + c T S T 7 Y F T W W 2 W 2 5 F 2
L3 W T [guerra?, faint] VN T S 9 2 L T N c 5 // [Anchora disse] DM 5 9 T 9 5 7 5 Q Z I 2 7 Z PHI PHI 2 9 Y 2 PHI
L4 + c 5 5 I Y S T W T L T Z PHI T L L Z F Y L N L Y 9 Z L Z 7 T I 2 W + c T S T / [A questo]
L5 [Bene ... e stato antiveduto questo] T PHI Z PHI P 9 Z I 2 PHI + c 2
L6 W T + c T q U T S Q Z 9 7 Y W T Q T N W 2 PHI 7 Y S Y I Y F 2 Q Q Y [Xpo ... in buono stato]
DOUBTS
- L3 after "W T": a faint group of six letters, lighter than the cipher ink, read here as the clear word
"guerra" written faintly (the memorandum has "a fare guerra a Viniziani"); not counted as cipher.
- L3 "S 9 2" = "sua": the S sign is followed by a small stroke, read as part of S.
- L4 "7 T" = "de" before "marchese": the memorandum has "del"; no l sign is seen.
- L5 "P 9 Z" (puo): the p sign there is a double stroke joined to a hook; counted as one sign P.
- L6 "q U": the q and u signs occur only here.
- L1 has "2 4 ffm(?)" in the middle of the clear text; read as a clear abbreviation, not counted.Transcription: no08.tok
Decryption
# Output of `python targets/siena8/decode.py` (key rebuilt from the alignment with the memorandum), saved 22 Oct 2026:
# each cipher run of the slip deciphered, beside the words of the contemporary memorandum (paragraphs 5-7) that decipher it.
51 signs cipher: legiereechapitolieleghafra[duca di Milano]elmarchesediferraraafare
memo: le|ggiere e capitagli e legha fral duca di Milano el marchese di Ferrara a fa|re
10 signs cipher: [Viniziani]esualegha
memo: a Viniziani e sua legha
59 signs cipher: [duca di Milano]aueuadatomadonnauianchaamisereleonellofilgliuolodemarchese
memo: el duca di Milano aveva dato la donna Biancha a misser Leonello figlolo del marchese
46 signs cipher: enonpuomancharechequestoudiretegrandisimifatti
memo: e no puo manchare che questo udrete grandissimi facti
cipher signs: 166 | distinct: 23Reading
<!-- Reading of Siena, Concistoro 2308 fasc. 2 no. 8 (R4797) (Claude Opus 5.5, 23 Oct 2026): the four cipher runs of texts/no08_decryption.txt (key rebuilt from the alignment with the contemporary memorandum on the same sheet, which deciphers them) divided into words, letters as the decode gives them; the two word signs as there, capitalised as resolved name signs ([Duca di Milano], [Viniziani]; 23 Oct 2026, v8: written lower-case they were counted as holes). The runs are separate pieces of the slip; the clear text between them is not in the repository, so each is a line of its own (the run-edge '…' marks were dropped on 23 Oct 2026, v8: they marked clear text, not unread cipher, and the scorer counted them as holes; the clear words before runs 3 and 4 are 'Anchora disse' (L3) and 'e stato antiveduto questo' (L5)). Cipher throughout. --> # Siena, Concistoro 2308 fasc. 2 no. 8 (DECODE R4797), c. 1440-41: reading of the cipher runs ## Reading legiere e chapitoli e legha fra [Duca di Milano] el marchese di Ferrara a fare [Viniziani] e sua legha [Duca di Milano] aueua dato madonna Biancha a misere Leonello, filgliuolo de marchese e non puo manchare che questo udirete grandisimi fatti.
Translation
<!-- English translation of texts/no08_reading.md (Claude Opus 5.5, 23 Oct 2026): the four cipher runs of the Siena slip no. 8 (R4797), deciphered with the key rebuilt from the contemporary memorandum on the same sheet. Separate pieces, as there. --> # Siena, Concistoro 2308 fasc. 2 no. 8 (DECODE R4797), c. 1440-41: English translation of the cipher runs … to [make] chapters and a league between the [Duke of Milan] and the Marquis of Ferrara, to make … … the [Venetians] and their league … The [Duke of Milan] had given Madonna Bianca to messer Leonello, the Marquis's son … … and it cannot fail that in this you will hear of very great deeds.
Key: key.json
06Sources
- Archivio di Stato di Siena, Concistoro 2308 fasc. 2 no. 8: DECODE R4797.
- George Lasry, “The cipher documents of Concistoro 2308, fasc. 2”, report of 17 October 2026, contents p. 3.
- A. Meister, Die Anfänge der modernen diplomatischen Geheimschrift (Paderborn 1902), pp. 50–51.
Manuscript rights: Archivio di Stato di Siena.
Transcription, decoder (decode.py), profile and notes: targets/siena8/.