At a glanceExternal key matched · partial (2% of the cipher)
- The letters
- Seven ciphered despatches of the Duke of Sessa to Charles V (20 February – 27 April 1523), catalogued as “Luis Fernández?” to an unknown recipient with nothing known of their content.
- Where
- Real Academia de la Historia, Madrid, Salazar A-27 (9/27); DECODE R9660–R9666 (110 pages). Four of the letters are in print as English abstracts in Bergenroth’s CSP Spain vol. 2.
- The cipher
- The Sessa nomenclator of 1523–25: three-letter code groups (
gapque,cohSu Santidad) mixed with spelled letters and clear words. - How it was read
- The key from the Sessa 1524 write-up applies unchanged. The 26 April letter is decrypted in full and the 20 February letter about 57%, with 15 values added from context.
- What it says
- The 20 February letter covers Adrian VI’s irresolution towards the French, Lannoy’s visit, and Soderini waging war on the Medici. The 26 April letter has a run saying the Pope is declared against France.
- Still open
- About 150 code groups of R9660 (about 40% of its tokens) have no attestation. The court’s decipherment leaves, at the RAH, would value them.
01The seven records
| DECODE | Salazar A-27 | Date line | Bergenroth, CSP Spain vol. 2 |
|---|---|---|---|
| R9660 | ff. 141–147 | En Sesa a xx de hebrero de 1523 | not calendared |
| R9661 | ff. 149–152 | En Roma, miercoles iiij de março 1523 | no. 534 (calendared from the f. 190 copy, “in cipher with contemporary deciphering”) |
| R9662 | ff. 308–326 | [12 April 1523] | no. 541, “a duplicate of the preceding despatch” |
| R9663 | ff. 327–341 | [11 April 1523] | no. 540 (ff. 327–343, “contemporary deciphering”) |
| R9664 | ff. 418–422 | De Roma xxv de abril 1523 | duplicate of no. 544 (ff. 424–430 deciphered) |
| R9665 | ff. 437–438 | De Roma xxvj de abril 1523 | not calendared |
| R9666 | ff. 439–441 | April 1523 | no. 545, clear |
The Emperor’s side of the same exchange (Valladolid, 8 and 15 February 1523, answering Sessa’s letter of 17 December) is in CSP nos. 528–530. Sessa’s 20 February letter opens with that December letter: A los xvij de dizienbre escrevi a V. M.
02A sample: the 20 February letter, f. 141r
Decrypted by hand with the 1524 key. Known groups are rendered as words, spelled letters are hyphenated and unvalued groups are in brackets:
¶ muy despues [cag] a [d3]-a-do a V.Md. de la con-[…] y forma que el papa [cas] / … el p-l-l-i-g-r-o m-a-n-i-f-… en que se ponian / la cosa … al [kor] con la c-e-r-t-i-z-a que el [yim] de … estonces dava / de la [bog]-da de franceses / el [bao] se [set] de [bla] a ve-r a Su Santidad, mas con color de … de ningun-… disposicion de entender / … y si no es … a lo que V.Md. [kim] se / entre tanto avisarle.
The clear resumes: Hizose asy. Fuimos en Roma a los xxvj del pasado; entro con muy buen recibimiento, y el posar fue en palacio. The full token list is in targets/sessa1523/reading_f141_sample.txt.
03The two uncalendared letters, decrypted (21 September 2026)
R9665, 26 April: decrypted in full. The letter is in clear apart from three short runs. The first, on f. 437r, decrypts with the key as Su Santidad por esta bula es declarado contra Francia, and a note in the margin, written when the letter arrived, says the same thing word for word. The note also gives one group the 1524 key lacked: hef = por. The two runs on f. 437v were deciphered between the lines at the time: …al de Ancona (Cardinal Accolti, praised as muy buen servidor de V. Mt.) and Su Sd. mejoro ayer.
R9660, 20 February: transcribed in full, decoded, not read. (Reading audit, 22 Oct 2026: open groups and spelled letters in nearly every line; only phrases can be built. The topics below are what the decoded phrases and the clear passages show.) About 2,050 cipher tokens on ff. 141r–147r, of which about 57% decrypt with the key extended by 15 values found in context: yim duque, bla ir, boz -io, loz obisp-, gam como, and the spelled V-o-l-t-e-r-a, which fixes three letter values. The letter covers Adrian VI’s irresolution towards the French and his refusal to join the league or give French envoys a safe-conduct; the viceroy Lannoy’s visit; Francis I’s plan to take a third of church revenue in France; the Swiss envoys’ pay; the Duke of Bari; Modena and Reggio against Alberto Pio, committed to Cardinals Volterra, Monte and Iacobacci; Soderini waging war on the Medici como enemigo; Siena after Petrucci’s death; the bishopric of Tortosa. Decryptions: targets/sessa1523/reading_r9660.txt, reading_r9665.txt.
Re-reading, 23 October 2026. No text of R9660 is reachable: the seven DECODE records of Salazar A-27 (R9660–R9666) and their neighbours R9656–R9659 and R9667–R9669 hold no decipherment of it; f. 141r is marked Dup.da, so this is the duplicate; and CSP Spain 2 has no Sessa letter of 20 February. The key values added in sessa1524 since September were applied to it (holes fall from 28% to 21% of tokens); six of them fail in an R9660 context and are left open here. Only the first cipher paragraph of f. 141r builds sentences (R9660_reading.md, English R9660_en.md):
A los xvij de dizienbre escrevi a vuestra magestad por via de Francia [q] en [?…] la letra al [?duque] de Bari, el qual me respondio aver la recibido y enbiado a vuestra magestad.
The rest stays decoded, not read: about 100 code groups (472 occurrences) are attested in no deciphered Sessa page, and the court’s decipherments of these letters are on leaves of the volume (ff. 190, 342–343, 424–430) that are not imaged.
04What remains
- About 150 code groups of R9660 (about 40% of its tokens; the commonest
cas,cag,min,rep) have no attestation in any decipherment on DECODE. The court’s decipherment leaves of the sister letters (ff. 190, 342–343, 424–430) would value them and are only at the RAH. - The calendared letters are in print only as English abstracts. The Spanish decipherments are on RAH leaves outside these records.
- The groups still open in the 1524 key (
vo,per,hay) are still unvalued;rucis a verb root, not a person. The sample’s word-level decryptions are grade C.
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.
R9660, Sessa, 20 Feb 1523 (RAH Salazar A-27 ff. 141r-147r) decoded, not read
The Duke of Sessa, imperial ambassador in Rome, to Charles V, from his duchy: no contemporary decipherment and not calendared by Bergenroth. Transcribed in full and deciphered in part (about 57%) with the 1524 Sessa key; the file gives each cipher line (a) with its reading (b), open groups in [ ]; it opens on letters sent 'por via de Francia' and 'la letra al duque de Bari'.
A mechanical decode with holes in most sentences: shown so that the transcription and the key can be checked and improved, not as a reading.
Transcription: reading_r9660.txt
Decryption: reading_r9660.txt
Decryption
R9660 = RAH Salazar A-27 (9/27) f. 141r, Sessa to Charles V, "En Sesa, xx de hebrero 1523". Second cipher paragraph (after the clear "... que hazer mi ninguna en el"), 11 lines, read by eye from the full-size image with the 1524 key (targets/sessa1524/key_working.md). f~ = the clear/cipher switch sign. [..] = sign not yet valued. cipher (by line) 1 f~ v db log sis cag α d3 ꝍ α ram α bas suf α tac g 3 4 do ꝑ put gap 2 qib Jap cas / d3 qid ram qib sof gap dim cob # d3 α / sof cih ꝑ do sat ttt 3 boz do f~ ꝑ qib nf 9 9 3 # ꝍ 4 v α do 3 oo Є gat f~ [clear: en que se ponian] f~ mus ꝍ 4 tas tt sof min f~ 3an kor tac mus ttt g ꝍ ott x ⅄ α gap qib yim sof 5 [..] α x 3 [clear: estonces dava] f~ suf α bog sad sof pu3 qes f~ qib bao dim set 6 sof bla α boe α coh f~ [clear: mas con color] f~ sof d3 cob ott α ꝍ ka gap sof [..] 7 sof lip α do α ott d ꝍ α sof len 4 f~ [..] cob net ꝍ α [clear: disposicion de entender] 8 f~ qid gob ꝍ njn [..] 9 ꝍ kef f~ ꝑ cob ler qes nf 9 ꝍ α d kef gap bas kim 9 dim f~ [clear: entre tanto avisarle. Hizose asy. Fuimos en Roma a los xxvj del pasado ...] reading (known groups in plain, spelled letters hyphenated, open groups in [ ]) ¶ muy despues [cag] a [d3]-a-do a V.Md. de la con-[g34 do] y forma que el papa [cas] / [d3] en-do el de que se si-g-[d3]-a / de su y [do sat ...] ... el p-l-l-i-g-r-o m-a-n-i-f-[Є gat] "en que se ponian" / la cosa [tt] de [min] / al [kor] con la c-e-r-t-i-z-a que el [yim] de [..]-a-i-r "estonces dava" / de la [bog]-da de franceses / el [bao] se [set] de [bla] a ve-r a Su Santidad, "mas con color" de [d3] si t-a-r-le que de [..] de ningun-a-n-a-t-a-r-a de [len]-o / [..] si [net]-r-a "disposicion de entender" / en [gob]-r-ha(n) [..] lo / y si no es p-l-r-a a lo que V.Md. [kim] se / "entre tanto avisarle". Sense (tentative): Sessa weighs how the Pope (Adrian VI) stands toward the French; he could go to see His Holiness "with the pretext" of something, finding no disposition to listen, and meanwhile to report. The clear continues: "Hizose asy. Fuimos en Roma a los xxvj del pasado; entro con muy buen recibimiento, y el posar fue en palacio ..." (the viceroy of Naples, Lannoy, whose Rome visit of January 1523 this letter reports). This is a sample, not a reading of the letter: about half the tokens resolve with the 1524 key, the rest need the token-tile work that sessa1524 used (hand, not key, is the obstacle: the 1523 hand is the same writer's).
Decryption: reading_r9660_b34.txt
Decryption
# R9660: the Duke of Sessa to Charles V, Sessa, 20 February 1523 (RAH Salazar 9/27 ff. 141r-147r), partial reading Re-read 23 Oct 2026 (Claude Opus 5.5, REREAD_BRIEF batch b34); log in `R9660_reread_log.md`. **Decoded, not read.** No decipherment, copy or print exists that this project can reach (log, section 1); the letter is the *duplicada* (so marked at the head of f. 141r), and the court's decipherments of Sessa's letters are kept in the RAH volume, not on DECODE. The reading below is the one paragraph of f. 141r that builds into sentences with the key as it stands after sessa1524 passes 16, 17 and b23 (`reading_r9660_b34.txt`), checked on a full-resolution crop of `IMG_R9660_I45473_P1.jpg`. The rest of the cipher (about 2,050 tokens, ff. 141r-147r) has a hole about every fifth word; it is kept as the decode file, not as a reading. Conventions: plain = carried by the figures (known group or spelled letters) or clear in the original; `[?word]` partly carried (a tentative key value, or one doubtful sign); `[word]` supplied; `[…]` unread; `[cag]` an unidentified code group. Spelling as the figures spell. ## Reading A los xvij de dizienbre escrevi a vuestra magestad por via de Francia [q] en [?…] la letra al [?duque] de Bari, el qual me respondio aver la recibido y enbiado a vuestra magestad. Muy despues [cag] avisado a vuestra magestad de la [tac g34 do] y [put] que el papa [?tiene], viendo el [?…] que se seguia de su in[?ten]c[?io]n y el peligro manifiesto en que se ponian las cosas de [min] al [kor] con la certeza que el [?duque] de Bari estonces dava de la [bog]da de franceses, el [bao] se [set] de [?ir] a ver a Su Santidad, mas con color de visitarle que de [ce3z] de ninguna natura de [?buen]o; [ꝍ3] si [?halla]ra disposicion de entender en [?ello]r […]lo, y si no es para lo que vuestra magestad [?manda]sse, entre tanto avisarle. Hizose asy. ## Notes - Cipher groups and the values used: `log` muy, `sis` despues, `bas` vuestra magestad, `suf` de la, `gap` que, `qib` el, `Jap` papa, `cas` tien- (pass 17, tentative), `ram` -do, `dim` se, `cob` si, `sof` de, `cih` su, `sat` ten (tentative), `boz` -io (pass 15/17), `mus` la, `tas` cosa, `ttt` plural, `3an` al, `tac` con, `yim` duque (pass 15), `pu3 qes` franceses, `bla` ir (pass 15), `boe` a ver, `coh` Su Santidad, `lip` ningun-, `len` buen- (pass 17, tentative), `net` halla (pass 16, attested in R9898), `gob` ello (pass 17, tentative), `kef` lo, `ler` no, `qes` es, `kim` manda- (pass 15, tentative). Clear words between `f~` switches: *en que se ponian*, *estonces dava*, *mas con color*, *disposicion de entender*, *entre tanto avisarle*. - Open in this paragraph: `cag`, `tac g34 do`, `put`, `min`, `kor`, `bog`, `bao`, `set`, `ce3z`, `ꝍ3`, and the run after *ello*. None recurs in a deciphered page of the 1523-1525 Sessa letters. - The first sentence is clear in the original except the cipher run *por via de Francia … la letra al duque de Bari*.
R9665, Rome, 26 Apr 1523 (ff. 437-438)
A mostly clear letter on the arrest of Cardinal Soderini of Volterra, with three short cipher runs, all read: 'Su Santidad por esta bula es declarado contra Francia' (confirmed by a contemporary margin note), the Cardinal of Ancona 'muy buen servidor de V. Mt.', and 'Su Sd. mejoro ayer'. The other records of this group (R9661-R9664) are duplicates of letters Bergenroth calendared from the court's decipherments (CSP Spain 2 nos. 534, 540, 541, 544); their ciphers are not transcribed here, and R9666 is clear.
Transcription
R9665 = RAH Salazar A-27 (9/27) ff. 437-438, Sessa to Charles V, "De Roma xxvj de abril 1523". Mostly clear (the arrest of Cardinal Soderini of Volterra, 27 Apr). Three short cipher runs, read with the sessa1524 key; two of them carry the receiving clerk's interlinear decipherment, the third a marginal summary. 1. f. 437r, lines 15-16 (after the clear "... se hizo esta tan buena demostrando"): cipher f~ coh hef qet b u l α qes sof ttt q α ⅄ α / ram tac ott ⅄ α [F] ⅄ α do ttt bay f~ reading Su Santidad por esta bula es de-c-l-a-r-a-do con-t-r-a F-r-a-n-c-ia gloss (left margin, contemporary) "Su Sd. por esta b[u]la es declarado contra Francia" The gloss and the key agree token for token. New value: hef = por (open in sessa1524). The F-sign (two tokens, "c o v"-like, after tac ott ⅄ α) is new; value fixed by the gloss. Clear continues: "viendo tomado[s] ... y mostrado ... por V. Mt. ..." 2. f. 437v, line 4: cipher f~ z an sof [α ott ttt 4 ob α] f~ gloss (interlinear) "... al de Ancona" reading [lo]s? al de A-n-c-o-n-a: the cardinal of Ancona (Pietro Accolti) Context (clear): "... para cardenales en recamara suya, y especialmente [al de Ancona]; en este caso se ha comportado como muy buen servidor de V. Mt." Letter-by-letter alignment of the name is tentative. 3. f. 437v, line 7: cipher f~ coh le g b o z d x z f~ gloss (interlinear) "Su Sd. mejoro ayer" reading Su Santidad me-j-o-r-o a-y-e-r (coh, le = me, d = a, x = e as in the key) So all of R9665's cipher is read: two runs were deciphered by the receiving clerk, and the third is confirmed by the margin note. The key applies unchanged apart from the new hef = por.
Decryption
R9665 = RAH Salazar A-27 (9/27) ff. 437-438, Sessa to Charles V, "De Roma xxvj de abril 1523". Mostly clear (the arrest of Cardinal Soderini of Volterra, 27 Apr). Three short cipher runs, read with the sessa1524 key; two of them carry the receiving clerk's interlinear decipherment, the third a marginal summary. 1. f. 437r, lines 15-16 (after the clear "... se hizo esta tan buena demostrando"): cipher f~ coh hef qet b u l α qes sof ttt q α ⅄ α / ram tac ott ⅄ α [F] ⅄ α do ttt bay f~ reading Su Santidad por esta bula es de-c-l-a-r-a-do con-t-r-a F-r-a-n-c-ia gloss (left margin, contemporary) "Su Sd. por esta b[u]la es declarado contra Francia" The gloss and the key agree token for token. New value: hef = por (open in sessa1524). The F-sign (two tokens, "c o v"-like, after tac ott ⅄ α) is new; value fixed by the gloss. Clear continues: "viendo tomado[s] ... y mostrado ... por V. Mt. ..." 2. f. 437v, line 4: cipher f~ z an sof [α ott ttt 4 ob α] f~ gloss (interlinear) "... al de Ancona" reading [lo]s? al de A-n-c-o-n-a: the cardinal of Ancona (Pietro Accolti) Context (clear): "... para cardenales en recamara suya, y especialmente [al de Ancona]; en este caso se ha comportado como muy buen servidor de V. Mt." Letter-by-letter alignment of the name is tentative. 3. f. 437v, line 7: cipher f~ coh le g b o z d x z f~ gloss (interlinear) "Su Sd. mejoro ayer" reading Su Santidad me-j-o-r-o a-y-e-r (coh, le = me, d = a, x = e as in the key) So all of R9665's cipher is read: two runs were deciphered by the receiving clerk, and the third is confirmed by the margin note. The key applies unchanged apart from the new hef = por.
Reading
<!-- Reading of R9665 (Claude Opus 5.5, 23 Oct 2026): the three cipher runs of reading_r9665.txt (decoded with the sessa1524 key, checked against the receiving clerk's interlinear and marginal decipherments), each in the clear words around it as reading_r9665.txt quotes them. An excerpt: the clear letter (the arrest of Cardinal Soderini) is not transcribed in the repository. Cipher in ⟦ ⟧; [lo]s? = the clerk's gloss partly covered, kept as [?los]. --> # R9665, the Duke of Sessa to Charles V, Rome, 26 April 1523 (RAH Salazar A-27 ff. 437-438): reading of the cipher runs ## Reading … se hizo esta tan buena demostrando: ⟦Su Santidad por esta bula es declarado contra Francia⟧; viendo tomado[s] … y mostrado … por V. Mt. … … para cardenales en recamara suya, y especialmente ⟦[?los] al de Ancona⟧; en este caso se ha comportado como muy buen servidor de V. Mt. … ⟦Su Santidad mejoro ayer.⟧
Translation
<!-- English translation of R9665_reading.md (Claude Opus 5.5, 23 Oct 2026): the three cipher runs of R9665 (in ⟦ ⟧) in the clear words around them. An excerpt. --> # R9665, the Duke of Sessa to Charles V, Rome, 26 April 1523: English translation of the cipher runs … this so good demonstration was made: ⟦His Holiness, by this bull, is declared against France⟧; seeing taken … and shown … by Your Majesty … … for cardinals in his chamber, and especially ⟦[?those] the one of Ancona⟧; in this case he has behaved as a very good servant of Your Majesty. … ⟦His Holiness was better yesterday.⟧
Key: key_working.md
05Sources
- Real Academia de la Historia, Madrid, Colección Salazar y Castro A-27 (signatura 9/27), via DECODE R9660–R9666 (images by permission of the Academia).
- G. A. Bergenroth, Calendar of State Papers, Spain, vol. 2 (1866), nos. 528–545: March 1523, April 1523.
- The key: Sessa 1524,
targets/sessa1524/key_working.md.
Notes, profile and sample reading: targets/sessa1523/ in the repository.