Champagne news letters to the duc de Nevers, 1590

Summary. The catalogue item grouped six letters to Louis de Gonzague, duc de Nevers, as one Champagne correspondence and proposed to test Tomokiyo’s seventy Nevers keys on them. They are three different things. No. 23, Bienvenut’s letter from Paris of the last day of February 1590, is a clear copy in which only nine persons and provinces are coded by small numbers, and the key is bound with it on the next leaf, so it decodes in full. Nos. 24, 25 and 60, news-letters of June 1590 in one hand, use a short two-digit homophonic alphabet whose values rise with the alphabet (a in the 30s, e in the 40s, n in the 60s, u in the 90s). A few letters written faintly above the figures of nos. 25 and 60 anchor it, and the order gives the rest. Ten of the twelve cipher passages are deciphered in whole or in part (“la rupture de l’edict [de] l’union”, “contre la ligue”, “du sieur Ludovic”). Tomokiyo’s key no. 46, the one used from Nevers’s office in 1593, does not fit. No. 78 has a single group of six signs and stays open. The Laurière letter of 9 July 1593 (fr. 3625 no. 55) is f. 66r, in a mixed syllabic code of figures and signs; the groups it shares with his 13 July letter (no. 10, f. 10r), which carries the office’s interlinear decipherment, decode it in fragments (“… que le Roy soit encores …”, “… la volonté du pape …”).

01 The documents

The BnF notice and the DECODE records give the folios: no. 23 f. 35 (key slip f. 36r), no. 24 f. 37, no. 25 f. 38, no. 60 f. 88, no. 78 f. 111 in fr. 3623; on Gallica canvas = 2 × folio + 9. The two letters bound between them, no. 26 (f. 39, from Sy, 11 January) and no. 27 (f. 41), are entirely in figures with a contemporary decipherment between the lines, but in another key.

02 No. 23: Bienvenut, Paris, 28 February 1590

Key slip with nine numbered entries — Fr. 3623 f. 36r, the key bound after the letter: 1 Le Roy d’Espaigne, 10 Le Pape, 15 Les villes de l’Union ou Provence & Dauphiné, 17 Le Duc de Parme ou Picardie, 36 Madame de Nemours, 35 Monsieur du Maine, 37 Monsieur de Nemours, 26 Le Roy, 53 Monsieur de St Sorlin. Image: Bibliothèque nationale de France, fr. 3623 f. 36r, via Gallica (btv1b525245007).

Every number in the letter is on the slip, so the letter decodes end to end (grade H). It is addressed to “Vostre Altesse” and reports the court of the League in Paris:

[Madame de Nemours] me pourmena hyer par la gallerie du logis de la Reyne plus d’une heure… elle me monstra plusieurs avis qu’elle avoit eu de [M. de Saint-Sorlin]… J’ay advis… qu’il y a une tres estroicte intelligence entre [le Pape] & [le Roy d’Espagne]… le courrier que Mr le Legat despescha a Rome… pour entretenir la guerre jusques a ce que [le Pape] puysse envoyer 8 ou 10000 hommes de guerre avec lesquelz il baste l’ame a [Mayenne]…

03 Nos. 24, 25, 60: an alphabetical two-digit key

Lines of clear text with runs of two-digit figures and faint letters above them — Fr. 3623 f. 38r, no. 25 of 5 June 1590: the cipher runs, with a few letters of decipherment written over single figures. Image: Bibliothèque nationale de France, fr. 3623 f. 38r, via Gallica (btv1b525245007).

The glosses give d u n i, a, n and, in no. 60, L u d o v i c. Set against the context they place a = 34/35, c = 37, d = 38, i = 53/54, l = 56/58, n = 63/64, o = 67, u = 93. The values rise with the alphabet, so every other figure has a predicted slot: e 42–45, f 46, g 47, h 48, r 74–75, s 82–86, t 92. Decryptions were accepted only when each value fell in its slot.

Where	Figures	Reading	Grade
25, “la rupture de l’edict”	12 58 93 63 54 67 64 19	[de] l’union [19]	C/I
25, “ne combatroient point contre”	56 34 56 54 47 93 43	la ligue	C/I
25, “Je a aussi”	39 38 42 56 34 38 43 46 54 35 63 37 42 38 93 17	[39] de la defiance du [17]	I
25, “qu’on dict”	17 33 53 56 82 45 38 45 46 54 43 38 93 39	[17] … se defie du [39]	I, first half open
25, “qui faict les affaires”	39 38 43 37 48 32 83 45 74 67 63	[39] de Chazeron	I
25, “vostre”	89 84 42 75 93 54 37 45	[89] service	I
60, “du sieur”	19 56 93 38 67 93 53 37	[19] Ludovic	C
60, “en est aussi”	39 38 43 56 35 94 62 32 64	[39] de la V?an	I, name open
24, “du faict”	99 38 39 45 30 93 38 67 92 52 37	open	—
24, “mal disposé”	16 39 56 43 99 95 93 35 92 05 54 86	open	—

Chazeron is named in clear in no. 24, which supports the decryption in no. 25. The figures below 30 and 39, 89, 99 behave as word or name codes and have no key.

04 Laurière, Châlons, 9 July 1593 (fr. 3625 no. 55)

The OAI item list of fr. 3625 places no. 55 at f. 66r (canvas 143): Laurière’s letter, “Chalons ce IX juillet 1593”, clear French with eight cipher runs (86 groups). The code mixes figures of one to three digits with letters and signs and is syllabic. Only “come” is written over the first group. His letter of 13 July (no. 10, f. 10r) is in the same code with the office’s decipherment between the lines; its first three runs give ✗ = que, 335 = le Roy, 141 = soit, 346 = volonté, 59 = du, XX = pape, 103 56nΔ = aussitost.

No. 55	Reading	Grade
347	come (gloss on the leaf)	H
25 ✗ 335 141 encores	… que le Roy soit encores	C
26.6. 346. 59 XX	… la volonté du pape	C
286 103 56nΔ	… aussitost	C

All seven glossed runs of no. 10 were then aligned into a code table of twelve entries. The code is syllabic: most words of the decipherment sit over two to five groups whose boundaries are not marked, so only groups that fall under the same word twice, or alone under a one-word gloss, were accepted. With that table 19 of the 86 groups of no. 55 are decoded, e.g. “come […] du que […]”, “[…] que le Roy soit encores […]”, “[…] a la volonté du pape […] aussitost”. The rest stays open; a language model has nothing to score with four groups in five unknown.

05 What stays open

The two passages of no. 24, the first half of one no. 25 passage, the name in no. 60, and the code numbers 12, 16, 17, 19, 39, 89, 99 (and 22, 44, 51, 84 in no. 24).
No. 78 (f. 111r, 1591): one group, “traictast de 96 □ 3 9̄ f 3”, too short to decrypt.
Fr. 3625 no. 55: 67 of 86 groups not decoded with the no. 10 table.

06 Sources

BnF français 3623, Gallica btv1b525245007, canvases 79–86 (ff. 35–38), 185 (f. 88), 233 (f. 111).
BnF français 3625, Gallica btv1b52511322v, canvases 31 (f. 10r, no. 10) and 143 (f. 66r, no. 55).
DECODE records R9453, R9454, R9455, R9459, R9460 (no decipherment on the records).
S. Tomokiyo, “Ciphers of the Duke of Nevers”, cryptiana.web.fc2.com/code/nevers.htm (keys of BnF fr. 3995; no entry for fr. 3623 or 3625).

Transcriptions, decipherments and the profile are in the repository folder champagne1590/.

Champagne news letters to the duc de Nevers, 1590–91