vo, per, ruc, hay) and one spelled clause occur in no deciphered sibling and stay open.
01The documents and their date
DECODE uploaded the Salazar volumes 9/26 to 9/39 in January 2026 as about a hundred records of Sessa and Lope Hurtado de Mendoza, in Rome from 1522 to 1526. Eight records in 9/31 carry the year 1424 (R9877 to R9884); the next ones, from the same volume and the same hands, carry 1524. The target leaf says so itself, on f. 128v: De Roma xviij de Abril 1524. The volume is the one Bergenroth cites as “M. Re. Ac. d. Hist. Salazar. A. 31” in the Calendar of State Papers, Spain, vol. 2.
| Bergenroth | Date | Letter | Salazar A-31 | DECODE |
|---|---|---|---|---|
| 637 | 14 Apr 1524 | Sessa → Emperor, “deciphered by Don Manuel de Goicoechea” | f. 79 | R9873, no decipherment bound |
| 639 | 17 Apr 1524 | Sessa → Emperor | ff. 138–140 | R9881, cipher f. 138, clear f. 140 |
| — | 18 Apr 1524 | Sessa → Emperor, and the duplicate | ff. 128–131 | R9877, R9878 |
| 643 | 22 Apr 1524 | Sessa → Emperor | ff. 163–173 | R9883, R9884, clear ff. 172–173 |
| 651 | 19 May 1524 | Sessa → Emperor | ff. 320–325 | R9890, clear ff. 324–325 |
The two copies of 18 April were written from one draft. Every cipher token recurs on f. 130 in the same order, so the duplicate gives a second image but no variant spellings. Bound as f. 131 is the Italian letter of 6 April from the imperial postmaster, tutti Elvetij son in arme … expedisca volando a Milano et Roma, which Sessa cites.
02The cipher
A nomenclator in a rounded chancery hand. Three-letter groups stand for words and syllables: gap que, sof de, mus la, dim se, coh Su Santidad, fad rey, Jep paz, bob tregua, cum suyços, po3 Francia, mef Inglaterra. Single signs spell: α a, 4 o, x e or i, ꝺ r, nf p, ott t, # g, tto z, and a p with a loop is the plural -s. A flourished f marks each change between clear and cipher, and v db opens each ciphered paragraph as a null.
| Group | Value | Where it was attested |
|---|---|---|
| rad | dicha | January 1525, la dicha letra |
| lif 3 | mostrar | 24 July 1524, ni se quiere mostrar |
| fa | quiere | 24 July 1524 |
| z y | -on | 8 September 1523, dilataron, concedieron |
| hud | plática | 22 April 1524, January 1525, 24 July 1524 |
| zum | hay | 24 July 1524, ni hay memoria |
| boy, bez | -ido | January 1525, perdido |
The full table, with the passage behind each value, is in the repository’s key_working.md.
03The letter of 18 April 1524
The letter opens in clear. Sessa had seen a letter of the Bishop of Veroli from Constance and sent to the Pope for particulars. Felice, the papal secretary, told him the bishop’s letters of the 6th and 7th reported that the Swiss diet was over and that Lucerne had not agreed to help the French. Bern, Fribourg and Solothurn, the letter goes on, were spreading word that the Swiss in Lombardy were surrounded, so as to raise eight thousand men. The bishop’s friends in Switzerland wanted him to urge the Pope towards some form of peace. Esto es lo que me ha referido.
Then nine lines of cipher. Code groups are resolved; a hyphen joins letters spelled sign by sign; brackets mark what is not deciphered; bold is clear text written between the cipher runs.
las dichas [—]s no le las mostraron, que le ponen sospecha que desea aver algo que refiera de lo suso [—] [—] no / me parece que concuerda mucho con lo primero y postrero que el dicho obispo dize al maestro de postas / hablé en la ora a Su Santidad a pedirle que haya provisión de [—]-r-a los casos de suyços, persuadiéndole los m-re que r-ido los que no m-r-e-van / pues tiene color para ello, aviendo començado la plática de la paz y tregua … entender lo que mas podré. Al visorrey escrivo en el mismo punto.
In English: The said [letters] they did not show him, for they make him suspect a wish to get something out of them … It seems to me that it agrees closely with the first and last of what the said bishop writes to the postmaster. I spoke at once to His Holiness to ask him to make provision [of money] for the Swiss business, persuading him … since he has a pretext for it, having begun the negotiation of the peace and truce … to learn what more I can. I write to the Viceroy at the same moment.
Bergenroth’s abstract of the 22 April letter (CSP Spain 2, no. 643) continues the story: the Pope and the Swiss disapprove of the disbanding of the army, and there is “no provision of money from His Holiness or the Florentines beyond what I wrote”.
04How the key was rebuilt
No key for this cipher survives, and none is in print. What survives is Sessa’s correspondence, and in a number of his letters the court wrote the decipherment on a separate leaf marked A Claro, B Claro. Each of those gives cipher and clear side by side. The work went through eight of them.
- Three letters of April and May 1524 gave the first 60 groups: f. 138 against f. 140 (17 April), ff. 168v–171 against ff. 172–173 (22 April), f. 322 against ff. 324–325 (19 May).
- Every cipher line was cut into images of single tokens by a script that splits the line at gaps in the ink, and each token was transcribed and aligned from its image. That separated look-alike signs the eye had merged: two p-loops (plural -s and b), two three-shapes (r and i), two hooked signs (d and u).
- Six more letters were fetched from DECODE: January and February 1525, 24 and 29 July 1524, and seven of 1523. The January 1525 letter gave dicha; 24 July gave mostrar, quiere and hay. The February 1525 letter carries no decipherment, despite its DECODE status.
- Template matching then searched every downloaded page, about 110, for the target’s groups still without a value, at five scales. The September 1523 letter gave -on, twice, in dilataron and concedieron.
05What remains uncertain
Grades follow the repository’s convention: C taken from a letter whose clear text is known, M uncertain, I inferred from context.
| Reading | Grade | Basis |
|---|---|---|
| las dichas … no le las mostraron | C | rad, lif, z y each attested in a deciphered sibling |
| que le ponen sospecha que desea aver algo | M | spelled letter by letter; one hooked sign is doubtful |
| que refiera de lo suso | I | z taken as o, the first half of -on |
| hablé en la ora a Su Santidad a pedirle que haya provisión | C | code groups attested; ora spelled |
| para los casos de suyços, persuadiéndole | C | cum suyços; persuadiendo spelled |
| la plática de la paz y tregua | C | hud attested three times |
Open:
vo, a noun after las dichas, presumably the bishop’s letters or their copies. No match in any page.per, before -ra los casos. No match in any page.rucandhay, after de lo suso. Both recur only in the letter of 14 April 1524 (R9873), which has no decipherment bound with it. Bergenroth says Goicoechea deciphered that letter for him in the nineteenth century. That decipherment is at the Academy and is the one source left for these two groups.- The clause los m-re que r-ido los que no m-r-e-van: every sign has a value, but the sequence is not yet Spanish, so one value in it is wrong.
06Sources
- Real Academia de la Historia, Colección Salazar y Castro A-31 (9/31) ff. 128–131, via DECODE R9877 and R9878 (images need a DECODE login).
- Deciphered siblings used for the key: R9881 (ff. 138–140), R9883 and R9884 (ff. 168–173), R9890 (ff. 322–325), R9893 (ff. 483–485), R9897 (9/34 ff. 10–16), R9834 (9/29 ff. 33–39); transcribed but not deciphered: R9873 (ff. 79–86), R9895, R9898.
- G. A. Bergenroth, Calendar of State Papers, Spain, vol. 2 (1866), nos. 630–654, on British History Online; the note on Goicoechea is under no. 637.
No page images are reproduced here: the scans are the Academy’s, served through DECODE to registered users.
Transcriptions, the key with its evidence, the token-cutting script and the template matcher are in the repository folder targets/sessa1524/.