Qua … n j c H d o 8 Lo & l 8 + u Z f s j c H …
(ten lines of homophonic substitution, with clear words mixed in)

Ratisbon → Milan · homophonic substitution · 12 June 1546 · read from existing decipherment

Marignano to Ferrante Gonzaga, 12 June 1546

A general at the imperial court reports to the governor of Milan that the war against the Lutherans is decided; the cipher passage is deciphered from the translation made at the time.

Daniel Bourdeau · posted

Method: read from existing decipherment · Extent: complete

Contributed by WAINUT (solution, transcription, verification)

At a glanceExisting decipherment · complete

The letter
Gian Giacomo Medici, marquis of Marignano, writes from Ratisbon on 12 June 1546 to Ferrante Gonzaga, governor of Milan. The letter is mostly in clear; ten lines on c. 13r are in cipher.
Where
Biblioteca Estense Universitaria, Modena, Autografoteca Campori, Lettera M, Medici, cc. 13–16. The record notes that c. 14 “contiene traduzione della porzione cifrata”. Not in the catalogue.
The cipher
A letter substitution with homophones, in signs that look like Latin letters and others. A small sigma-shaped sign is a null, and eti is a code for V. Ecc.a. Double letters are written once. Words are divided by commas and slashes.
How it was deciphered
This is a transcription job, not a break. The contemporary clear translation at the top of c. 14r covers the whole cipher passage, and the key was rebuilt from it.
What it says
The war against the Lutherans is decided. Provisions are being made, and the writer sends to Milan and Genoa for men for the artillery.
Still open
Three signs are doubtful, the f or sigma in two words is unsettled, and four groups of dotted vowels (nulls or stops) are not proved either way. No human palaeographer checked it, and the images were not seen here.
Credit
WAINUT (an AI company) transcribed the signs, rebuilt the key and read the passage with AI agents viewing the images.

01 The letter

From the imperial court at Ratisbon, Marignano tells Ferrante Gonzaga that the war against the Lutherans is decided. After the clear opening come ten lines of cipher (306 signs and groups); the letter then goes on in clear, mentioning the despatch to Milan and Genoa for men for the artillery. c. 13v carries the date and signature, and the address and the docket “Il M.se di Marignano” are on c. 14v. Below the translation on c. 14r is a clear postscript about Sebastiano de Perego, which is not part of this reading.

02 The cipher and its key

Vowels have two or more signs (for example a is j or 8). Several sign names carry two values; most are probably two similar shapes merged under one name in the transcription, and they are flagged in key.tsv. The key was rebuilt step by step from the clear translation and frozen before the final counts. The check script aligns each reading with its decryption letter by letter and fails on any departure from the signs that is not marked.

03 The reading

All 62 cipher words read as sense. 55 come verbatim from the signs and 7 carry a marked repair: four double letters restored, two doubtful signs and one sign read against its value. 59 of 62 (95.2%) have no departure from the signs other than the scribe’s single-written double letters. An independent check gives 60 of 62 (96.8%). Seven clear words in the passage are not counted. The Italian and an English translation are under Full texts.

04 What remains uncertain

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.

12 June 1546, c. 13r (cipher)

From the imperial court at Ratisbon, Marignano tells Ferrante Gonzaga that the war against the Lutherans is decided. Provisions are being made and he has a large part in them; the preparation is great and he will send a detailed report by the next courier. The court professes to keep the matter secret, though it is already public; Ferrante is not to name him as the source.

Transcription

transcription_c13r.txt

# Marignano to Ferrante Gonzaga, 12 June 1546, c. 13r: the cipher, sign by sign, after two passes and adjudication
# (validation/adjudication.tsv); M08 quale corrected 9 -> g after the independent check (3 Nov). Sign names describe shapes, not values (legend in scripts/pass2_blind.py), plus:
#   H  = the double-crossed sign (named # in the pass legend)
#   l  = a looped script l with descender (M01 only; pass 1 called it g; doubtful, written l?)   s = a small sigma-shaped sign (pass 1 merged it with f)
#   dd = d with a cross on the ascender                                      W = omega (M04) as distinct from w = lying double loop (M01)
#   Lo, 1o = L or a plain stroke joined to o, copied as one group            ? after a sign = doubtful on the image
#   {onu} {nao} {nou} {anu} = groups of dotted vowels standing apart         [word] = clear word in ordinary script
#   eti = a code written like a clear word (V. Ecc.a)
M01	[Qua] {onu} n j c H d o 8 , Lo & / l? 8 + u Z f s j / c H X D a 8 , n u q e a j X w
M02	, Z , T e a / k Z 9 H n D j / 9 & 8 c f Z X Lo Z / j t s e / T a H u & g e s r X Z
M03	{nao} e D , & H . X H X , n e s , h 8 X c r , Lo & / g u 8 X D H , v H dd o H
M04	Z , X e , + H , T & u , Lo & , v 8 a D Z / {nou} [Hora] 9 & c H W ,
M05	X H 9 c e a j , [meglio] . eti , [L'aparechio] , Z , + a j X Lo H ,
M06	, e , T Z a , & n , v a & o H , X Z , h 8 X 1o j a H , T 8 a D & [cular]
M07	j u & 9 H , j'? , eti , F u j 9 & N j T a H q Z dd o & H X Z Lo &
M08	D Z X e a [questa] [cosa] {anu} H c u n D 8 , g u j n Z , + & j . Z
M09	T u o? n & c j , T Z a H , eti , X H X , h & . X Z , 1 j N & j , o Z ,
M10	j u c f H a Z {nao} :
Decryption

decryption_c13r.txt

# Decryption of c. 13r, rebuilt by scripts/decode.py from transcription_c13r.txt and key.tsv.
# Per line: the signs, then the values (a|b = sign name with two values, null = no letter, ? = doubtful sign).
M01	signs	{onu} n j c H d o 8 Lo & l 8 + u Z f s j c H X D a 8 n u q e a j X w
M01	values	null l a c o s s|m a d i l? a g|h u|v e r|t null a c o n t r a l u|v t|f e|i r a n i
M02	signs	Z T e a k Z 9 H n D j 9 & 8 c f Z X Lo Z j t s e T a H u & g e s r X Z
M02	values	e p e|i r r e s o l t a s i a c r|t e n d e a l null e|i p r o u|v i s|q e|i null o n e
M03	signs	{nao} e D & H X H X n e s h 8 X c r Lo & g u 8 X D H v H dd o H
M03	values	null e|i t i o n o n l e|i null m a n c o d i s|q u|v a n t o p o s s|m o
M04	signs	Z X e + H T & u Lo & v 8 a D Z {nou} 9 & c H W
M04	values	e n e|i g|h o p i u|v d i p a r t e null s i c o g
M05	signs	X H 9 c e a j eti Z + a j X Lo H
M05	values	n o s c e|i r a [V. Ecc.a] e g|h r a n d o
M06	signs	e T Z a & n v a & o H X Z h 8 X 1o j a H T 8 a D &
M06	values	e|i p e r i l p r i s|m o n e m a n d a r o p a r t i
M07	signs	j u & 9 H j' eti F u j 9 & N j T a H q Z dd o & H X Z Lo &
M07	values	a u|v i s o a? [V. Ecc.a] q u|v a s i f|c a p r o t|f e s s|m i o n e d i
M08	signs	D Z X e a {anu} H c u n D 8 g u j n Z + & j Z
M08	values	t e n e|i r null o c u|v l t a s|q u|v a l e g|h i a e
M09	signs	T u o n & c j T Z a H eti X H X h & X Z 1 j N & j o Z
M09	values	p u|v s|m? l i c a p e r o [V. Ecc.a] n o n m i n e f a f|c i a s|m e
M10	signs	j u c f H a Z {nao}
M10	values	a u|v c r|t o r e null
Reading

reading_c13r.md

# Marignano to Ferrante Gonzaga, Ratisbon, 12 June 1546, c. 13r: reading of the cipher (Italian)

The cipher passage of c. 13r as the signs give it. Clear words that the writer mixed into the cipher are in *italics*.

Files: `reading_marked_c13r.txt` (line by line, checked by `scripts/check_marks.py`), `translation_c13r.md` (English),
`clear_c14r.txt` (the contemporary clear translation on c. 14r).

Marks: `(x)` = a letter with no sign, since the cipher writes double letters once. `[?x]` = a letter on a doubtful sign.
`{b}` = read b where the sign as named gives s. Null signs and the dotted-vowel groups are left out here.
*V. Ecc.a* expands the code `eti`.

## Italian

*Qua* la cossa di [?l]a guer(r)a contra luterani è per resolta, si actende al(l)e provisione, et io non li manco di quanto
posso, e ne ho più di parte. *Hora* si cognoscerà *meglio* V. Ecc.a. *L'aparechio* è grando, e per il primo ne mandarò
parti*cular* aviso [?a] V. Ecc.a. Qua si fa professione di tenir *questa cosa* oc(c)ulta, quale già è pu{b}lica. Però
V. Ecc.a non mi ne fac(c)ia me auctore.

## Notes on the text

- Spellings are the writer's and are kept: *cossa*, *di la*, *actende*, *grando*, *mandarò*, *auctore*. The translation
  on c. 14r has *della*, *grande* and *autore*.
- Double letters are written once in the cipher: *guera*, *ale*, *oculta*, *facia*.
- *pu{b}lica*: the third sign is a doubtful o-like sign (`o?`). Elsewhere `o` is s or m. The word rests on the sense and
  on c. 14r.
- *di [?l]a*: the l is a looped script l with a descender. It occurs once and is doubtful on the image. c. 14r has *della*.
- *aviso [?a]*: the sign is the hooked d (a) with an inner dot or stroke, which is doubtful.
- *per il primo*: by the first courier. c. 14r abbreviates it as "p.o".
- The last sentence on c. 14r reads "però V. Ecc.a no' [?mi ne] [?faccia] me autore". Some letters there are small and
  doubtful.
- An earlier rough reading of that line, "no' mancarà me avisare", was wrong.
Translation

translation_c13r.md

# Marignano to Ferrante Gonzaga, Ratisbon, 12 June 1546, c. 13r: English translation of the cipher

Same marks as `reading_c13r.md`: `[?x]` doubtful; `{b}` read against the sign as named. "Your Excellency" expands the code
`eti` (V. Ecc.a).

Here the matter of the war against the Lutherans is resolved. Provisions are being made, and I do not fail in them as far
as I can, and I have a part in them, more than my share. Now it will be better known, Your Excellency. The preparation is
great, and by the first [courier] I will send a detailed report [?to] Your Excellency. Here they make a profession of
keeping this matter secret, which is already pu{b}lic. But let Your Excellency not make me its author [do not name me as
the source].

Notes: *si cognoscerà* is impersonal ("it will be known"). The clear translation on c. 14r runs "Hora si cognoscerà meglio
V. Ecc.a l'apparecchio è grande" with no stop, so the sentence boundary before *L'aparechio* is uncertain, and "V. Ecc.a"
may belong to either sentence. *ne ho più di parte* is rendered loosely. In *di la* (M01) the *l* stands on a doubtful sign.

Key: key.tsv, key_frozen.tsv

05 Sources

Working files: targets/marignano1546/ in the repository.