The cipher of Cardinal Scipione Gonzaga and the Duke of Nevers, 1590

Document

Paris, BnF, ms. français 4698 (Gallica btv1b9058291p, microfilm): letters in Italian from Cardinal Scipione Gonzaga in Rome to Louis de Gonzague, Duke of Nevers, with long passages in cipher. Here: the letters of 21 January 1590 (ff. 30r-31r) and of 24 March 1590 (ff. 26v-27r).

New

The reconstruction of the cipher, built without a key sheet: three layers, a word code of 448 values in 14 lists, a symbol alphabet. The link between fr. 4698 and the period decipherments in fr. 4702. A test of the rebuilt code on a second volume, fr. 4696. The letters of 24 March and 31 March 1590, which have no period decipherment, read with gaps.

Reproduced

The plain text of the letters of 21 January and 16 February 1590. It is the text of Nevers's own clerk of 1590 (BnF fr. 4702). We transcribed and translated it. It is not a new decipherment.

The key

1. A word code. A two-digit figure, 10 to 99, stands for one word in its dictionary form. A mark on the figure says which list the figure belongs to. Each list is a slice of one alphabetical word list; u and v count as one letter.

The names of the lists are ours. On the microfilm lists A and C both carry a dot above most of the time; the word decides between them. Full table: tables/lists_v4.tsv (448 values, each with its period gloss). Proposals with no gloss: tables/interp_v4.tsv.

2. A symbol alphabet for words that are not in the lists. The images are cut from f. 30r, lines 1 to 3, of the letter of 21 January 1590. The names of the signs are ours.

qoaaasigaatribb#cddcc=dllddTetet2eperpeexxffcagglggKhhviLiiF3lF3rllpimxummoXnQnnphiophidoohoalooRpgampprryrrSsxissomtom2ttEuE3ushupivuu, v

In each box: the sign, our name for it, and its letter. A box with no image: the sign is not in these three lines. Source of the sign images: BnF, ms. français 4698, f. 30r (microfilm), gallica.bnf.fr / BnF. The table of the signs is in the work log: evidence/worklog.md.

3. A verb sign. An arc above a figure means: read the verb of the noun in the list. The Cardinal states this rule in clear on f. 17v.

Worked example

21 January 1590: f. 30r, cipher line 1, with the text of the clerk of 1590

Each box holds one unit: the figure, its mark as we read it on the film and the list, the word of the rebuilt code (dictionary form), and the word that the clerk wrote in 1590. A red box: we keep another word than the clerk.

62bar below, dot below; list Ssodisfationesodisfatione 28two bars; list PTcheche 32bar above; list NPapaPapa 73dot below; list Mmostraremostrare (32)in brackets; list BRhaverecosì 82dot above; list Cdidi 94circumflex above; list Opersonapersona 10bar above; the mark names list N, the word is in list Tsuasua #c aa cag vi phido oXn qoa om2t sigacagionatacagionata61caron below; list Pprincipaleprincipale 69no mark; the mark names list A, the word is in list Cdada 39no mark; list A; figure read 39 beforealcunoalcuno 79bar below; list Iletteralettera 82dot above; list Cdidi (36)in brackets; list BRleilei 81caron below; the mark names list P, the word is in list Qritenereritenere ◇diamond with a dotetet 52dot above; the mark names list C, the word is in list Aapertoaperto 79bar below; the mark names list I, the word is in list PToltreoltre 67two dots below; list Gilil 32bar below; the mark names list I, the word is in list Ssdegnosdegno 30dot above; the mark names list C, the word is in list Aaggiungereaggiungere 83two bars; list PTperper 99caron below; list Pquelloquello 28two bars; list PTcheche (25)in brackets; list BRsisi (39)in brackets; list BRsonosono 

Clerk, fr. 4702 f. 94r, lines 3 to 6: V(?) Ecc. di molt[struck: itudine] cosa ma particolarm.te di poco sodisfatione che Papa mostra così di persona sua cagionata principalm.te da alc.o [struck: dimodo] lettera di lei ritenuto et aperto oltre il sdegno aggiunta per quello che si sono visto del Volta et quello che lui andava spargendo di V.E.

Edition (the clerk's text with agreement made regular): sodisfatione che Papa mostra [havere] di persona sua, cagionata principalmente da alcune lettere di lei ritenute et aperte, oltre il sdegno aggiunto per quello che si sono

the little satisfaction that the Pope shows with your person. Its main cause is some letters of yours that were held and opened; added to this is the anger at what was seen of Volta

In 7 of the 26 figure units of this line the mark that we read on the film names another list than the list of the clerk's word. In 1 unit we keep another word than the clerk: for (32) he wrote "così", and the list has "havere". The clerk writes the dictionary form of each word, with no agreement.

24 March 1590: f. 26v, line 13. No period text is known for this letter

Each box holds one unit of the transcription: the figure, its mark and the list that the mark names, and the word of the table. Italic boxes are clear words of the letter. A word in {braces} has no period gloss: it is a proposal inside its alphabetical window.

Et {in somma}(?) il parere di quasi tutti *fu* che non conveniva a dignità di Papa *il far alcuna delle* cose domandate se non con debito termine, et dopo

And {in short}(?) the opinion of almost all was that it did not befit the dignity of the Pope to do any of the things asked, except in due time, and after

The code gives dictionary forms; number, gender and tense in the reading are ours. In the reading file, *..* marks clear text and (?) a doubt. The figure 10 without a mark has two values in the table, "a" and "Ambasciatore".

How sure

Outside check. After the reading, the statements of the two letters of March 1590 were compared with L. von Pastor, History of the Popes, vol. 21, pp. 343-362. Pastor confirms 19 of 22 statements of the first letter and 7 of 11 of the second. For the letter of 21 January the check is the clerk of 1590 himself.

What is not resolved

• No key sheet was found. The cipher is on black-and-white microfilm: one dot against two dots often cannot be decided, and a wrong mark gives a wrong word that looks real. In about one unit in ten the mark that was read names another list.
• 24 March 1590: 17 units are not resolved, and 41 words are proposals. The name of the person who left Rome is a code that is not resolved.
• Four words of the March readings were shaped by what the history says; the reading files mark them.

Editions and readings: editions/edition_1590-01-21_f30.txt, reading/f26v-27r_1590-03-24.md. Folder: gonzaga-1590.