972Unsolved Historical Ciphers
ω4ʋȝ α8 ωα → the, of, to
that his faith is not vendible

Henri IV’s court → Lord Treasurer Burghley · simple substitution in invented symbols, inline with clear English · 1592–1594

Thomas Edmondes to Burghley, 1592–1594

Thomas Edmondes
fromThomas Edmondes
William Cecil
toWilliam Cecil

BL Stowe MS 166 ff. 50–61, 109–112 (DECODE R7770–R7775), catalogue item 140. The DECODE record names “Lord Threr?” as the author, but the Lord Treasurer is the addressee. The letters are reports from the King’s camp in Edmondes’s papers. The key was recovered here from the ciphertext alone, and all cipher passages are deciphered except four lines on f. 59. An earlier decipherment exists: G. G. Butler printed five of the six letters, with the cipher passages deciphered, in The Edmondes Papers (1913). It was found on 30 September 2026, after the key had been recovered here.

Daniel Bourdeau · posted · updated

Method: key recovered from ciphertext-only · Extent: partial (89% of the cipher)

Summary. The catalogue had five DECODE records of “Lord Threr? to unknown recipient”, 1592–94, marked Non-decrypted (no decipherment known). There is a sixth, R7771, in the same run. They are letters to the Lord Treasurer, Burghley, among the papers of Thomas Edmondes, Elizabeth’s agent with Henri IV. The writer reports what the King told him in person, and dates from Tours, Blois and the camp before Laon. In each letter a few lines are written in invented symbols inside the clear English. The cipher is a simple substitution of English, keeping word divisions, with a few homophones and single symbols for persons. The key was recovered from the ciphertext alone by taking frequent cipher words as the, of and to, and the same key serves all six letters, in two hands. Every passage is deciphered except four lines on f. 59. The passages include the King breaking off his sister’s marriage to [Soissons?], Montmorency’s demand for custody of the young Prince of Condé, a would-be purchaser told “that his faith is not vendible”, and [Guise?]’s designs on Champagne and Reims in 1594. Butler’s Edmondes Papers (1913) prints five of the six letters with the cipher deciphered. That was found only after the key had been recovered here, so this break is an independent re-solution. The letter on ff. 109–110 is the one Butler leaves out.
Stowe MS 166 f. 50, clear English breaking into six lines of invented signs
Stowe MS 166 f. 50 (R7770): “as it pleaseth himself to tell me) as especiallye”, then six lines of cipher, “to breake of the marriage betwene her and [9]…” Image: British Library, Stowe MS 166 f. 50, via DECODE R7770.

01 The letters

DECODEff.datecipher
R777050–51[Chartres, 19 January 1592/3]6 lines
R777156–57Tours, 16 February 1592/34 lines
R777258–59Tours, 3 March 1592/36 + 4 lines
R777360–61Blois, 16 March 1592/32 lines
R7774109–110camp before Laon, July 159410 lines
R7775111–112[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).

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.” The four cipher lines that continue on f. 59 are not deciphered here: only “papistes” and a few other words are certain. Butler prints them on his p. 56, but his wording has not been seen yet.

Stowe MS 166 f. 60v, two cipher lines after 'saide vnto me'
f. 60v (R7773): “but the K. thereuppon saide vnto me”, then in cipher that his faith is not vendible. Image: British Library, Stowe MS 166 f. 60v, via DECODE R7773.

f. 60v (R7773). “…but the K. thereuppon saide vnto me that his faith is not vendible.”

f. 109v (R7774). “…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, [?] 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; the said townes…”

f. 112 (R7775). “[£2]: execute an enterprise vppon Rheins wch would be the ca[…]inge of the place and him. The King hath a disposition to geve him the Gouernment of Provence to embarque him against the D. Espernon…”

04 What stays open

05 Sources

Notes and profile: targets/stowe166/ in the repository.