At a glanceCiphertext-only break · complete
- The letters
- Six despatches to the Lord Treasurer, Burghley, from Henri IV’s court, January 1593 to July 1594, among the papers of Thomas Edmondes, Elizabeth’s agent in France; a few lines of each in cipher inside the clear English.
- Where
- British Library, Stowe MS 166 ff. 50–61 and 109–112; DECODE R7770–R7775, catalogued as “Lord Threr?” to an unknown recipient, not deciphered.
- The cipher
- A simple substitution of English in invented symbols, keeping the word divisions, with a few homophones and single symbols for persons.
- How it was deciphered
- Key recovered from the ciphertext alone, taking frequent cipher words as the, of and to; one key for all six letters. Every passage was transcribed letter for letter and measured on 3 October 2026, after f. 109v and f. 112 were checked again on the images.
- What it says
- The King breaking off his sister’s marriage to [Soissons?]; Montmorency’s demand for the custody of the young Prince of Condé; “that his faith is not vendible”; [Guise?] and Champagne in 1594.
- Credit
- G. G. Butler, The Edmondes Papers (1913), prints five of the six letters deciphered; found after the key was recovered here.
- Still open
- Who the eleven person symbols stand for (no key with names survives), and one unexplained sign on f. 109v.

01 The letters
| DECODE | ff. | date | cipher |
|---|---|---|---|
| R7770 | 50–51 | [Chartres, 19 January 1592/3] | 6 lines |
| R7771 | 56–57 | Tours, 16 February 1592/3 | 4 lines |
| R7772 | 58–59 | Tours, 3 March 1592/3 | 6 + 4 lines |
| R7773 | 60–61 | Blois, 16 March 1592/3 | 2 lines |
| R7774 | 109–110 | camp before Laon, July 1594 | 10 lines |
| R7775 | 111–112 | [camp before Laon, 23 July 1594] | 3 lines |
Edmondes wrote the English year, which began on 25 March, so the letters dated January to March 1592 belong to 1593 in modern reckoning. Butler prints them under 1593, and the bracketed dates are his.
The DECODE “sender” fields (John le Rios, John Symmons, “Permell of Dieppo”, “One of Dieppe”) come from endorsements. The letters themselves are written by someone at the King’s side, in Edmondes’s papers.
02 The key
A = δ, b = +, c = 2, d = ш, e = ʋ, f = 8, g = б/6, h = 4, i = ǂ, k = 7, l = 3, m = □, n = ȝ, o = α, p = 9, r = f, s = &, t = ω, u/v = ш or a small o, w = π, x = 5, y = λ. ш serves for d as well as u/v, and б for a as well as g. Code symbols for persons: 9 standing alone (probably the Count of Soissons, 1593); n (a suitor for Catherine de Bourbon; Love (2001), quoting the same sentence from the letter as Burghley received it, glosses him as the Duke of Montpensier (M)); £, £2 (probably the Duke of Guise, 1594); o, a small circle, twice on f. 109v (by context the King, I). Eleven occurrences in all.
03 The decipherments
f. 50 (R7770). “…the K. continueth his resolution to goe to Saumur to see his sister, not so much for that cause (as it pleaseth himself to tell me) as especiallye to breake of the marriage betwene her and [9] wch he tould me he is resolued not to permitt but to geive her vnto [n] of whom he said he hath great hope that he will render himself of the religion. [9] is herewth enraged and extreemelie discontented.”
f. 57 (R7771). “…by the Pope, will appeare vnto yor L. by the enclosed. [9]: is glad to here of, hoping to be no further troubled wth the clamor of the Catholikes for the seekinge of him.”
f. 58v (R7772). “I doe secretelie learne that Monsr Montmorancy hath made great instance, as a condition whereof he required the performance before he would come, to haue the yong prince of Condé deliuered into the handes of Madame d’Angolesme his sister in law to be vnder his custodie.”
f. 59 (R7772), deciphered 2 October 2026. The four cipher lines at the head of f. 59 continue that sentence: “and by consequence popis[h]lie nourished, pretending so to appertaine to the place of the Constable, to haue the gouer[n]ment of the younge heire of the crowne, but wherein he hath nothing effected, the K. being resolued not to assent thereunto.” The young heir of the crown is the Prince of Condé of f. 58v. They were transcribed from the full-resolution DECODE image and read with the key unchanged, 126 signs for 126 letters, except for one sign that occurs only here, a vertical stroke for q in consequence. The fragments recorded before, “papistes” and an “effected” in cipher, were misreadings: the cipher word is popislie, and effected is in the clear ending. All twenty distinct words of the decipherment stand, in Butler’s modern spelling (popishly, appertain, government), on his p. 56 in the HathiTrust word data, against ten on the next best page of the volume; his page text itself could not be opened.


f. 60v (R7773). “…but the K. thereuppon saide vnto me that his faith is not vendible.”
f. 109v (R7774), lines 1–2 checked again on the image on 3 October 2026. After the clear “and whereas,”: “[9]: of whome especiallie [o] hath made choise expreslie to negotiate therein, for the difficulties of empeachement wch he knoweth he will geive to the same in respect of his owne interest against [£] pretending for the gouernment of Champaigne, [o] hauing no desire it should nowe take place, the rather for that he hath renewed his intelligences in Amiens and Rheins by the meanes of the duke [3:] the said townes…” The earlier reading began at choise; the symbol before hauing, left as [?], is the same small circle as in line 1, a person symbol.
f. 112 (R7775). “[£2]: execute an enterprise vppon Rheins wch would be the carryinge of the place and him (the r and y written as one ligature, re-read on the image on 3 October 2026). The King hath a disposition to geve him the Gouernment of Provence to embarque him against the D. Espernon…”
04 What stays open
- Who the person symbols stand for. 9 = Soissons and £ = Guise fit the context (M); n is the Duke of Montpensier in Love’s gloss (M). o, twice on f. 109v, is by context the King (I). No key with names survives: Tomokiyo’s Elizabethan tables have no Edmondes cipher, Unton’s cypher of 1591 is a different system, and DECODE has no Edmondes key record (checked 2 October 2026); HMC Salisbury IV and Birch (1749) print no decipherment naming them, and the Calendar of State Papers Foreign for 1592–94 is not online. F. 59 has no person sign. These eleven signs and the “3:” of f. 109v are the twelve of 1,035 not read.
- The new sign on f. 59, a vertical stroke for q, occurs once (C).
- The sign “3:” before the said townes on f. 109v (after the clear “by the meanes of the duke”) is not explained. “Hope” and “marriage” on f. 50 are under blots (C). Measured on 3 October 2026 over a letter-for-letter transcription of every passage (
reading.txt,measure.py): 1,023 of 1,035 signs read, 98.8%, and 99.9% leaving out the person symbols. The earlier figure of 95% was an estimate. - Butler’s wording, pp. 46–59 and 148–151, to be compared with the decipherments here. HathiTrust refuses this project’s automated requests, so the check so far rests on HathiTrust’s page-by-page word counts. The words of every passage deciphered here stand on the matching Butler page (all 17 for f. 58v; a few others are garbled by the OCR of his italics), next to a note on the cypher.
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.
R7770, f. 50, [Chartres, 19 Jan 1593]
Henri IV goes to Saumur to break off his sister Catherine de Bourbon's marriage to [9] (probably the Count of Soissons) and means to give her instead to [n], of whom he has great hope that he will turn Protestant; [9] is enraged.
Decryption
# Stowe MS 166 (DECODE R7770-R7775): every cipher passage, deciphered letter for letter with the volume key
# (NOTES.md "The cipher"). 3 Oct 2026. One cipher sign = one letter here (simple substitution, word division kept), so
# the letters count the cipher signs. Marks: {..} = person code signs (one sign each); <..> = signs not read.
# Editorial brackets are not used: misspellings are kept as written. measure.py counts the shares.
# R7774 and R7775 were re-checked against the DECODE images on 3 Oct 2026 (R7774 lines 1-2 added; R7775 "carryinge").
#
R7770 f. 50 | {4̇} to breake of the marriage betwene her and {9} wch he tould me he is resolued not to permitt but to geive her vnto {n} of whom he said he hath great hope that he will render himself of the religion {9} is herewth enraged and extreemelie discontented
R7771 f. 57 | {9} is glad to here of hoping to be no further troubled wth the clamor of the catholikes for the seekinge of him
R7772 f. 58v | {9} i doe secretelie learne that monsr montmorancy hath made great instance as a condition whereof he required the performance before he would come to haue the yong prince of conde deliuered into the handes of madame dangolesme his sister in law to be vnder his custodie
R7772 f. 59 | and by consequence popislie nourished pretending so to appertaine to the place of the constable to haue the gouerment of the younge heire of the crowne
R7773 f. 60v | that his faith is not vendible
R7774 f. 109v | {9} of whome especiallie {o} hath made choise expreslie to negotiate therein for the difficulties of empeachement wch he knoweth he will geive to the same in respect of his owne interest against {£} pretending for the gouernment of champaigne {o} hauing no desire it should nowe take place the rather for that he hath renewed his intelligences in amiens and rheins <3> the said townes
R7775 f. 112 | {£2} execute an enterprise vppon rheins wch would be the carryinge of the place and himR7771, f. 57, Tours, 16 Feb 1593
[9] is glad of the news, hoping to be no further troubled with the clamour of the Catholics.
Decryption
# Stowe MS 166 (DECODE R7770-R7775): every cipher passage, deciphered letter for letter with the volume key
# (NOTES.md "The cipher"). 3 Oct 2026. One cipher sign = one letter here (simple substitution, word division kept), so
# the letters count the cipher signs. Marks: {..} = person code signs (one sign each); <..> = signs not read.
# Editorial brackets are not used: misspellings are kept as written. measure.py counts the shares.
# R7774 and R7775 were re-checked against the DECODE images on 3 Oct 2026 (R7774 lines 1-2 added; R7775 "carryinge").
#
R7770 f. 50 | {4̇} to breake of the marriage betwene her and {9} wch he tould me he is resolued not to permitt but to geive her vnto {n} of whom he said he hath great hope that he will render himself of the religion {9} is herewth enraged and extreemelie discontented
R7771 f. 57 | {9} is glad to here of hoping to be no further troubled wth the clamor of the catholikes for the seekinge of him
R7772 f. 58v | {9} i doe secretelie learne that monsr montmorancy hath made great instance as a condition whereof he required the performance before he would come to haue the yong prince of conde deliuered into the handes of madame dangolesme his sister in law to be vnder his custodie
R7772 f. 59 | and by consequence popislie nourished pretending so to appertaine to the place of the constable to haue the gouerment of the younge heire of the crowne
R7773 f. 60v | that his faith is not vendible
R7774 f. 109v | {9} of whome especiallie {o} hath made choise expreslie to negotiate therein for the difficulties of empeachement wch he knoweth he will geive to the same in respect of his owne interest against {£} pretending for the gouernment of champaigne {o} hauing no desire it should nowe take place the rather for that he hath renewed his intelligences in amiens and rheins <3> the said townes
R7775 f. 112 | {£2} execute an enterprise vppon rheins wch would be the carryinge of the place and himR7772, ff. 58v-59, Tours, 3 Mar 1593
Edmondes learns secretly that Montmorency demanded, as a condition of coming, that the young Prince of Condé, heir of the crown, be delivered to Madame d'Angoulême to be brought up in his custody, popishly, as belonging to the Constable's place; the King would not assent.
Transcription
# BL Stowe MS 166 f. 59 (DECODE R7772, image IMG_R7772_I35130_P3), the four cipher lines at the head of the page. # Transcribed 2 Oct 2026 from the full-resolution DECODE image, signs as in the NOTES key table; words as written. # '|' = the vertical-stroke sign (q, new: only in "consequence"); [blot] = an ink blot over a struck sign. L1: бȝш +λ 2αȝ&ʋ|шʋȝ2ʋ 9α9ǂ&3ǂʋ ȝαшfǂ&4ʋш 9fʋωʋȝшǂȝб L2: &α ωα б99ʋfωбǂȝʋ ωα ω4ʋ 93б2ʋ α8 ω4ʋ 2αȝ&ωб+[blot]3ʋ L3: ωα 4бшʋ ω4ʋ бαшʋf□ʋȝω α8 ω4ʋ λαшȝбʋ 4ʋǂfʋ α8 L4: ω4ʋ 2fαπȝʋ, # decrypt (letter for letter, 126 signs = 126 letters; with the Stowe 166 key; б = a in "haue", g in "pretending", "younge") L1: and by consequence popislie nourished pretending L2: so to appertaine to the place of the constable L3: to haue the gouerment of the younge heire of L4: the crowne, # then in clear: "but wherein he hath nothing effected, the K. being resolued not to assent thereunto."
Decryption
# Stowe MS 166 (DECODE R7770-R7775): every cipher passage, deciphered letter for letter with the volume key
# (NOTES.md "The cipher"). 3 Oct 2026. One cipher sign = one letter here (simple substitution, word division kept), so
# the letters count the cipher signs. Marks: {..} = person code signs (one sign each); <..> = signs not read.
# Editorial brackets are not used: misspellings are kept as written. measure.py counts the shares.
# R7774 and R7775 were re-checked against the DECODE images on 3 Oct 2026 (R7774 lines 1-2 added; R7775 "carryinge").
#
R7770 f. 50 | {4̇} to breake of the marriage betwene her and {9} wch he tould me he is resolued not to permitt but to geive her vnto {n} of whom he said he hath great hope that he will render himself of the religion {9} is herewth enraged and extreemelie discontented
R7771 f. 57 | {9} is glad to here of hoping to be no further troubled wth the clamor of the catholikes for the seekinge of him
R7772 f. 58v | {9} i doe secretelie learne that monsr montmorancy hath made great instance as a condition whereof he required the performance before he would come to haue the yong prince of conde deliuered into the handes of madame dangolesme his sister in law to be vnder his custodie
R7772 f. 59 | and by consequence popislie nourished pretending so to appertaine to the place of the constable to haue the gouerment of the younge heire of the crowne
R7773 f. 60v | that his faith is not vendible
R7774 f. 109v | {9} of whome especiallie {o} hath made choise expreslie to negotiate therein for the difficulties of empeachement wch he knoweth he will geive to the same in respect of his owne interest against {£} pretending for the gouernment of champaigne {o} hauing no desire it should nowe take place the rather for that he hath renewed his intelligences in amiens and rheins <3> the said townes
R7775 f. 112 | {£2} execute an enterprise vppon rheins wch would be the carryinge of the place and himDecryption
# BL Stowe MS 166 f. 59 (DECODE R7772, image IMG_R7772_I35130_P3), the four cipher lines at the head of the page. # Transcribed 2 Oct 2026 from the full-resolution DECODE image, signs as in the NOTES key table; words as written. # '|' = the vertical-stroke sign (q, new: only in "consequence"); [blot] = an ink blot over a struck sign. L1: бȝш +λ 2αȝ&ʋ|шʋȝ2ʋ 9α9ǂ&3ǂʋ ȝαшfǂ&4ʋш 9fʋωʋȝшǂȝб L2: &α ωα б99ʋfωбǂȝʋ ωα ω4ʋ 93б2ʋ α8 ω4ʋ 2αȝ&ωб+[blot]3ʋ L3: ωα 4бшʋ ω4ʋ бαшʋf□ʋȝω α8 ω4ʋ λαшȝбʋ 4ʋǂfʋ α8 L4: ω4ʋ 2fαπȝʋ, # decrypt (letter for letter, 126 signs = 126 letters; with the Stowe 166 key; б = a in "haue", g in "pretending", "younge") L1: and by consequence popislie nourished pretending L2: so to appertaine to the place of the constable L3: to haue the gouerment of the younge heire of L4: the crowne, # then in clear: "but wherein he hath nothing effected, the K. being resolued not to assent thereunto."
R7773, f. 60v, Blois, 16 Mar 1593
The King tells Edmondes 'that his faith is not vendible'.
Decryption
# Stowe MS 166 (DECODE R7770-R7775): every cipher passage, deciphered letter for letter with the volume key
# (NOTES.md "The cipher"). 3 Oct 2026. One cipher sign = one letter here (simple substitution, word division kept), so
# the letters count the cipher signs. Marks: {..} = person code signs (one sign each); <..> = signs not read.
# Editorial brackets are not used: misspellings are kept as written. measure.py counts the shares.
# R7774 and R7775 were re-checked against the DECODE images on 3 Oct 2026 (R7774 lines 1-2 added; R7775 "carryinge").
#
R7770 f. 50 | {4̇} to breake of the marriage betwene her and {9} wch he tould me he is resolued not to permitt but to geive her vnto {n} of whom he said he hath great hope that he will render himself of the religion {9} is herewth enraged and extreemelie discontented
R7771 f. 57 | {9} is glad to here of hoping to be no further troubled wth the clamor of the catholikes for the seekinge of him
R7772 f. 58v | {9} i doe secretelie learne that monsr montmorancy hath made great instance as a condition whereof he required the performance before he would come to haue the yong prince of conde deliuered into the handes of madame dangolesme his sister in law to be vnder his custodie
R7772 f. 59 | and by consequence popislie nourished pretending so to appertaine to the place of the constable to haue the gouerment of the younge heire of the crowne
R7773 f. 60v | that his faith is not vendible
R7774 f. 109v | {9} of whome especiallie {o} hath made choise expreslie to negotiate therein for the difficulties of empeachement wch he knoweth he will geive to the same in respect of his owne interest against {£} pretending for the gouernment of champaigne {o} hauing no desire it should nowe take place the rather for that he hath renewed his intelligences in amiens and rheins <3> the said townes
R7775 f. 112 | {£2} execute an enterprise vppon rheins wch would be the carryinge of the place and himR7774, f. 109v, camp before Laon, July 1594
On the choice of [9] to negotiate, against the interest of [£] (probably the Duke of Guise) who seeks the government of Champagne and has renewed his intelligences in Amiens and Reims.
Decryption
# Stowe MS 166 (DECODE R7770-R7775): every cipher passage, deciphered letter for letter with the volume key
# (NOTES.md "The cipher"). 3 Oct 2026. One cipher sign = one letter here (simple substitution, word division kept), so
# the letters count the cipher signs. Marks: {..} = person code signs (one sign each); <..> = signs not read.
# Editorial brackets are not used: misspellings are kept as written. measure.py counts the shares.
# R7774 and R7775 were re-checked against the DECODE images on 3 Oct 2026 (R7774 lines 1-2 added; R7775 "carryinge").
#
R7770 f. 50 | {4̇} to breake of the marriage betwene her and {9} wch he tould me he is resolued not to permitt but to geive her vnto {n} of whom he said he hath great hope that he will render himself of the religion {9} is herewth enraged and extreemelie discontented
R7771 f. 57 | {9} is glad to here of hoping to be no further troubled wth the clamor of the catholikes for the seekinge of him
R7772 f. 58v | {9} i doe secretelie learne that monsr montmorancy hath made great instance as a condition whereof he required the performance before he would come to haue the yong prince of conde deliuered into the handes of madame dangolesme his sister in law to be vnder his custodie
R7772 f. 59 | and by consequence popislie nourished pretending so to appertaine to the place of the constable to haue the gouerment of the younge heire of the crowne
R7773 f. 60v | that his faith is not vendible
R7774 f. 109v | {9} of whome especiallie {o} hath made choise expreslie to negotiate therein for the difficulties of empeachement wch he knoweth he will geive to the same in respect of his owne interest against {£} pretending for the gouernment of champaigne {o} hauing no desire it should nowe take place the rather for that he hath renewed his intelligences in amiens and rheins <3> the said townes
R7775 f. 112 | {£2} execute an enterprise vppon rheins wch would be the carryinge of the place and himR7775, f. 112, [camp before Laon, 23 Jul 1594]
[£2] (probably Guise) is to execute an enterprise upon Reims, which would be the carrying of the place; in clear, the King thinks of giving him the government of Provence against Épernon.
Decryption
# Stowe MS 166 (DECODE R7770-R7775): every cipher passage, deciphered letter for letter with the volume key
# (NOTES.md "The cipher"). 3 Oct 2026. One cipher sign = one letter here (simple substitution, word division kept), so
# the letters count the cipher signs. Marks: {..} = person code signs (one sign each); <..> = signs not read.
# Editorial brackets are not used: misspellings are kept as written. measure.py counts the shares.
# R7774 and R7775 were re-checked against the DECODE images on 3 Oct 2026 (R7774 lines 1-2 added; R7775 "carryinge").
#
R7770 f. 50 | {4̇} to breake of the marriage betwene her and {9} wch he tould me he is resolued not to permitt but to geive her vnto {n} of whom he said he hath great hope that he will render himself of the religion {9} is herewth enraged and extreemelie discontented
R7771 f. 57 | {9} is glad to here of hoping to be no further troubled wth the clamor of the catholikes for the seekinge of him
R7772 f. 58v | {9} i doe secretelie learne that monsr montmorancy hath made great instance as a condition whereof he required the performance before he would come to haue the yong prince of conde deliuered into the handes of madame dangolesme his sister in law to be vnder his custodie
R7772 f. 59 | and by consequence popislie nourished pretending so to appertaine to the place of the constable to haue the gouerment of the younge heire of the crowne
R7773 f. 60v | that his faith is not vendible
R7774 f. 109v | {9} of whome especiallie {o} hath made choise expreslie to negotiate therein for the difficulties of empeachement wch he knoweth he will geive to the same in respect of his owne interest against {£} pretending for the gouernment of champaigne {o} hauing no desire it should nowe take place the rather for that he hath renewed his intelligences in amiens and rheins <3> the said townes
R7775 f. 112 | {£2} execute an enterprise vppon rheins wch would be the carryinge of the place and himKey: key.md
05 Sources
- British Library, Stowe MS 166, via DECODE R7770, R7771, R7772, R7773, R7774, R7775.
- T. Birch, An Historical View of the Negotiations between the Courts of England, France, and Brussels, 1592–1617 (1749), drawn from the Edmondes papers; searched, and these passages are not in it.
- G. G. Butler (ed.), The Edmondes Papers (Roxburghe Club, 1913), nos. XVIII, XXI–XXIII and LXVI (pp. 46–59, 148–151): five of these letters, printed from Stowe MS 166 with the cipher deciphered; the letter on ff. 109–110 is not included. Checked on 30 September 2026 from the HathiTrust Research Center word counts for HathiTrust mdp.39015083993017; the page text has not been seen.
- R. S. Love, Blood and Religion: The Conscience of Henri IV, 1553–1593 (Montreal, 2001), quotes the f. 50 sentence and “faith is not vendible” from the letters as Burghley received them, now in the State Papers.
Notes and profile: targets/stowe166/ in the repository.

