Siena no. 21: “Karissimo come padre” (15th century)

At a glanceNot solved · text not obtained

The letter: An informal letter opening “Kar(issi)mo come padre”, about a letter received and one written; dated a day of August(?), without year or place, and signed with a cipher group and a clear “vostro”.
Where: Archivio di Stato di Siena, Concistoro 2308, fasc. 2 “Lettere in cifra”, no. 21; DECODE R4809 (Concistoro_2308_63), catalogued “1500–1599” with no status.
The cipher: Crosses, a double-barred cross, three uprights under one bar, plain, divided and filled squares, Λ, a hooked stroke and letter-like signs: about 35 signs. A name in line 1 is also put into cipher.
How it was tried: The filed keys of the busta were compared with its signs, and the key of no. 8 too; homophonic annealing was run on it.
Why it resists: 107 signs over some 35 sign types is too short without a key; no gloss or decipherment.
Credit: George Lasry’s report of 17 October 2026 places it among the fifteenth-century Sienese ciphers and lists it as not yet deciphered (109 symbols).

The other pieces of the Sienese cipher file are listed by key on the Concistoro 2308 index. No. 19, no. 14 and no. 25, under the same heading of George Lasry’s report (“one key each”), are different ciphers, with their own pages.

01The letter

The first two lines are mostly clear, in a fast and faded hand (“… la nostra lettera per … scripsi che per … vi convenne etc.”); the next two are mostly cipher, with a few clear words. The salutation is not one for the Signori, so this may be a private letter that reached the Sienese government, intercepted or handed over. There is no address on the photographed side.

A short letter of four lines; the last two lines are mostly crosses, barred uprights and squares, and the signature below is a square and barred uprights before the word vostro — The letter: clear opening lines, two lines of cipher, the date line at lower left and the ciphered signature “… vostro” at lower right. Image: Archivio di Stato di Siena, Concistoro 2308 fasc. 2 no. 21, via DECODE R4809.

02How it was tried

The alphabets of the keys of fascicle 1 compared by eye with the letter’s signs (24 September 2026): the cross-and-square signs recall none of them.
Homophonic annealing on the short pieces of the bundle: no convergence at this length.
The key of no. 8, rebuilt on 18 October 2026: a different sign set.

03What remains

All 107 cipher signs (George Lasry counts 109), the name in line 1 and the signature group among them. Writer, recipient and year are unknown.

04Sources

Archivio di Stato di Siena, Concistoro 2308 fasc. 2 no. 21: DECODE R4809.
George Lasry, “The cipher documents of Concistoro 2308, fasc. 2”, report of 17 October 2026, contents p. 2.

Manuscript rights: Archivio di Stato di Siena.

Transcription and profile: targets/siena21/.