At a glanceExisting decipherment · complete
- The letter
- Lieutenant Colonel Thomas Jordan, Beauregard’s adjutant, to “My Dearest Rachel”, Rose O’Neal Greenhow, summer 1861, seized at her house on 23 August 1861. A clear letter with words and parts of words in cipher.
- Where
- National Archives, RG 59, Seized Correspondence of Rose O’Neal Greenhow: the cipher original is naId 6925618, a photostat of burnt fragments (catalogue entry 646); the clear copy is naId 1634051, images 1–2 (catalogue entry 645).
- The cipher
- One symbol per letter, the system of the 1864 key sheet found on Greenhow’s body (NARA M1091, naId 62017285, image 0484).
- How it was deciphered
- The clerk’s copy gives every cipher passage in plain words, and a lighter hand wrote “h a r” under the first group on the original. Matched sign by sign, the 1864 key gives the copy’s letter for all 82 securely transcribed signs.
- What it says
- Jordan asks for Hardee’s and Scott’s Tactics, Mahan’s Field Fortification, eight yards of navy-blue flannel and shoulder straps for a lieutenant colonel: “These books are essential to me in my position”.
- Still open
- Three short stretches of the fragment (a line before “handed”, a central strip, the end of “for the rest to”) are too faint or torn; the copy has dashes there too.
- Credit
- The identification of the two items as one letter, the transcription and the key match by WAINUT (pull request #100, 27 October 2026), done with AI language-model agents. The decipherment is the clerk’s copy of 1861.
01 Two items, one letter
NARA’s naId 6925618, “Copy of a Letter Fragment Partially Written in Cipher”, is a white-on-black photostat of burnt and torn fragments pasted on a sheet: clear words with groups of symbols, cross-written in places. The catalogue had it as a letter from Greenhow to an unknown contact, written at Washington.
In the file “Letters from Lieutenant Colonel Thomas Jordan to Mrs. Greenhow and to My Dearest Rachel” (naId 1634051), images 1–2 are a fair copy in a clerk’s copperplate of a letter to “My Dearest Rachel”, all in clear, with dashes where the original is lost. Every clear phrase of the fragment (“to get for me”, “and if to be had conveniently / 8 yards navy flannel (blue)”, “for the rest to”, “me from Alex”, “essential to me in my / position as”, “by sending”) is in the copy, in the same order, so the fragment is the original of the copied letter, and the copy is its decipherment. Who made the copy, and when, the images do not show; a Federal clerk working on the seized papers is likely but not proved. Images 3–6 of the same file are a different clear letter and an envelope.
02 The key on the fragment
The 1864 key sheet (see the mourning-paper letter, which deciphers with the same key) was applied unchanged to the fragment’s 22 cipher groups, 89 signs, transcribed on inverted and contrast-stretched crops. Of the 82 signs transcribed without doubt, all 82 give the letter the clear copy has at that place: HAR(dee’s), (Tacti)CS, (n)EW COP(ies), SCOTT, (Tact)ICS, (vol)UMES, (Ma)HANS FIELD FORTIFICATION, (Sh)OULDER, (Str)APS, LIE(utenant), CO(lonel), (b)RIN(g), ANY, CAN G(et), HIM, BOO(ks), LIEU(tenant), COLONEL, IN(fantry).
Controls (decode.py): 20,000 random substitution keys average 3.1 of the 82 signs (best 36); the key shifted by 1, 2, 3 or 13 letters gives none; the true key with the groups set against the wrong words of the copy averages 5.5 (best 19); 22 of 22 groups come out whole, against at most 4 for a random key. The signs were transcribed knowing the copy’s text, but the key comes from a separate document of 1864 and each sign was matched to it by shape, so the bias is limited to the seven signs marked doubtful.
Points of detail: the first sign of HAR’s group is an O-sign (J on the key) that is not explained; SCOTT and BOO write their doubled letters plainly, not by the sheet’s inverted-second-letter rule; the first sign of OULDER may be the key’s sh digraph.
03 What it says
The fragment with the copy’s words supplied in brackets (cipher in capitals):
… to get for me HAR[dee’s Tacti]CS, [or the n]EW COP[ies of] SCOTT[’s Tact]ICS, [also … vol]UMES [of Ma]HANS FIELD FORTIFICATION[s], and if to be had conveniently 8 yards navy flannel (blue) [Indigo …]ing of [SH]OULDER [STR]APS for a LIE[utenant] CO[lonel. … handed …] he [will b]RIN[g] ANY you CAN G[et to] [H]IM, [and I will …] for the rest to […] me from Alex[andria …]. These BOO[ks are] essential to me in my position as LIEU[tenant] COLONEL of IN[fantry] and you will [do me a great favor] by sending [them by hand …].
Jordan, newly a lieutenant colonel, asks “Rachel” for the drill and engineering manuals of the day and for the cloth and insignia of his rank, to be sent by hand. On the first page of the copy he fears that an earlier letter did not reach her: he had no access to his cipher at the time, and a letter “in ordinary cha[racters]” “was intercepted”. The content is domestic. Its interest is the cipher: it shows the Jordan–Greenhow system in use in 1861 with the key found on Greenhow three years later. Jordan himself wrote on 29 October 1861 that he had arranged this cipher “last April”, hastily, under the alias Thomas John Rayford (Official Records, Series II, vol. 2, pp. 564–565).
04 What remains open
- Three stretches of the fragment are not transcribed: line 12 before “handed”, the central strip, and the end of “for the rest to”. The signs are faint or torn, and the copy has dashes at two of them.
- The copy’s dashes: the original is torn at those places too, and the surviving cipher does not fill them.
- Seven signs are doubtful (marked in the transcription) and are left out of the count of 82.
- The date: after Jordan became a lieutenant colonel and before the seizure of 23 August 1861. The place is presumed to be Beauregard’s headquarters at Manassas.
- No printed text of the letter was found: not in the Official Records, Series II, vol. 2 (pp. 561–577), Pinkerton’s Spy of the Rebellion or Greenhow’s My Imprisonment. Fishel and Blackman could only be searched through the web.
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.
Jordan to 'My Dearest Rachel', 1861: cipher original naId 6925618 read in part
Thomas Jordan, newly a lieutenant colonel, asks 'Rachel' (Rose Greenhow) to get him Hardee's and Scott's Tactics, Mahan's Field Fortification, 8 yards of navy-blue flannel and shoulder straps for his rank, to be sent by hand; the clear copy adds that he feared an earlier letter had failed to reach her: he had then no access to his cipher, and a letter in ordinary characters 'was intercepted' (the copy has gaps here). Domestic in content, but it shows the Jordan-Greenhow cipher in use in 1861 with the same key as in 1864.
Builds coherent sentences, but under the read bar of 95% of words read as sense (68% here); the holes are marked in the reading.
Transcription
# Jordan to "My Dearest Rachel" (Greenhow), 1861: the cipher original, sign transcription
# NARA RG 59, Seized Correspondence of Rose O'Neal Greenhow, naId 6925618, "Copy of a Letter Fragment Partially
# Written in Cipher", 1 image (hd1-135695281-2013-001-ac.jpg): https://catalog.archives.gov/id/6925618
# A white-on-black photostat of burnt and torn fragments pasted on a sheet; clear words mixed with sign groups;
# cross-written in places. Read on inverted, contrast-stretched crops, twice, independently.
#
# Signs as shape labels (the labels of ../greenhow1861/transcription_side1.txt; values in ../greenhow1861/key_1864.md):
# hk + with small x (A) b7 7 (B) c3 3 (C) cx + with small x lower right (D) yf Y (E) tr triangle (F)
# e8 8 (G) cm comb (H) f4 A with a star stroke (I) o0 O (J) ls long s (L) dd diamond with dot (M)
# qm ?-hook (N) f5 5 (O) cc circle with cross (P) ph psi / looped 4 (R) bx box with X (S)
# dt D with dot (T) e8s struck 8 / $ (U) fl flag triangle (W) ys Z over a stem (Y)
# "clear:" = words written in clear. | = gap between groups. ? after a label = uncertain sign. [..] = torn or faint.
#
# LEFT BLOCK
L1 clear: to get for me | o0? cm hk ph :
(under cm hk ph a lighter hand has written "h a r" letter by letter: an interlinear gloss;
":" after the group looks like an abbreviation mark; the leading O is unexplained)
L2 c3 bx
L3 yf fl? | c3 f5 cc
(the second sign may be an A with a stroke; W is not certain)
L4 bx c3 f5 dt dt
L5 f4 c3 bx | e8s? dd yf bx -
(the first sign of the second group is an 8 with an extra stroke, read as the struck 8 = U, as in R7)
L6 cm hk qm bx | tr f4 yf ls cx [ink blot]
L7 tr f5 ph dt f4 tr f4 c3 hk dt f4 f5 qm
(one small star-like stroke between the second F and the I, taken as cross-writing; the second triangle has
a stroke through it)
L8 clear: and if to be had conveniently / 8 yards navy flannel (blue)
L9 clear: [..]ing of | bx? f5 e8s ls cx yf ph
(the first sign is an hourglass-box: S, or the sh digraph of the key sheet; the fourth is a long s)
L10 hk? cc bx | clear: for a | ls f4 yf
L11 c3 f5 [..] (the rest of the line too faint, overwritten)
L12 [circle with dots?] [psi?] [triangle?] [..] | clear: handed (not read)
# CENTRAL STRIP
C1 [Z with a stroke?] f5 = / [+?] c3 (not read; not securely placed)
# RIGHT BLOCK
R1 clear: he in[?] 6[?] , | ph f4 qm
R2 hk qm ys | clear: you | c3 hk qm e8
R3 cm? f4 dd (the first sign is an arch with a dot)
R4 clear: of l[..]ss / 6 [..] (cross-writing, torn; not read)
R5 clear: for the rest to | ph qm? [..] (not read)
clear: me from Alex[..]
R6 clear: These | b7 f5 f5 ,
R7 clear: essential to me in my / position as | ls f4 yf e8s
R8 c3 f5 ls f5 qm yf ls | clear: of | f4 qm?
R9 clear: and you will [..] / [..] by sending [..] (and a tail flourish)
#
# Doubled letters (SCOTT, BOO) are written plainly; the 1864 key sheet's rule "2d letter itself inverted" is not
# seen at this resolution.Decipherment of the time
# The clear copy of the same letter: NARA naId 1634051, images 1-2 (hd1-65865167-2006-001/002)
# https://catalog.archives.gov/id/1634051
# NARA RG 59, Seized Correspondence of Rose O'Neal Greenhow, file "Letters from Lieutenant Colonel Thomas Jordan to
# Mrs. Greenhow and to My Dearest Rachel". A fair copy in a clerk's copperplate; the dashes are the copyist's and
# mark gaps. It gives in plain words the passages that are in cipher on the original (naId 6925618), so it is the
# decipherment of the time. Who made it, and when, is not shown on the images.
# Transcribed line by line.
## Image 1
My Dearest Rachel
I wrote you -
-ly - . do -
demands on you -
imposing not - her -
but confident of your wish to -
serve and do me favors, I did not
hesitate. I fear however that letter
failed to reach you, and as at the time
I had not access to my cypher,
in ordinary cha -
was intercepted
inconvenience
I sh -
## Image 2
in - if you -
to get for me Hardee's Tactics, or the new
Copies of Scott's Tactics, also - volumes
of Mahans field fortifications, and if to
be had conveniently 8 yards Navy flannel
(blue) Indigo - Shoulder Straps for a
Lieutenant Colonel. - handed -
he will bring any you can get to him,
and I will - for the rest - me from Alex-
-andria - - - -
These books are essential to me in my
position as Lieutenant Colonel of Infantry
and you will do me a great favor by
sending them by hand -Decryption
# Jordan to "My Dearest Rachel", 1861 (naId 6925618): decryption line by line against transcription.txt
# Key: 1864 Greenhow key, NARA M1091 naId 62017285 image 0484 (../greenhow1861/key_1864.md). python decode.py.
# CAPITALS = cipher signs with their key value; lower case inside a cipher group = uncertain sign;
# clear words in lower case as on the fragment; after "->": the clear copy (naId 1634051 image 2) at that place.
L1 to get for me j? HAR : -> to get for me Hardee's (interlinear gloss "h a r"; leading sign unexplained)
L2 CS -> (Tacti)cs
L3 E w? | COP -> (n)ew Cop(ies)
L4 SCOTT -> Scott('s)
L5 ICS | u? MES - -> (Tact)ics, (vol)umes
L6 HANS | FIELD -> (Ma)hans field
L7 FORTIFICATION -> fortification(s)
L8 and if to be had conveniently / 8 yards navy flannel (blue) (clear; the copy adds "Indigo -")
L9 [..]ing of | s? OULDER -> [..]ing of (sh)oulder (copy: "Shoulder")
L10 a? PS | for a | LIE -> (str)aps for a Lie(utenant)
L11 CO [..] -> Co(lonel)
L12 [not read] handed -> "- handed -"
C1 [not read] -> not placed
R1 he in[?] 6[?] , RIN -> he (will b)rin(g)
R2 ANY you CANG -> any you can g(et)
R3 h? IM -> (to) him
R4 of l[..]ss / 6 [..] -> not read (torn cross-writing)
R5 for the rest to R n? [..] -> "for the rest -" (the copy has a dash here)
me from Alex[..] -> me from Alex-andria
R6 These BOO , -> These boo(ks)
R7 essential to me in my / position as LIEU -> ... position as Lieu(tenant)
R8 COLONEL of I n? -> Colonel of In(fantry)
R9 and you will [..] / [..] by sending [..] -> and you will (do me a great favor) by sending (them by hand)
Totals: 22 groups, 89 signs; 82 read securely, all 82 give the clear copy's letter at that place.Reading
# Jordan to "My Dearest Rachel", 1861: the cipher original (naId 6925618) as sentences English, so no translation. Words read from cipher groups are in CAPITALS; clear words on the fragment are in lower case; words or letters that are torn away on the fragment and supplied from the clerk's clear copy (naId 1634051 image 2) are in [brackets]; [...] = lost and not in the copy either; [?] = uncertain. ## Reading ... to get for me HAR[dee's Tacti]CS, [or the n]EW COP[ies of] SCOTT['s Tact]ICS, [also ... vol]UMES [of Ma]HANS FIELD FORTIFICATION[s], and if to be had conveniently 8 yards navy flannel (blue) [Indigo ...]ing of [SH]OULDER [STR]APS for a LIE[utenant] CO[lonel. ... handed ...] he [will b]RIN[g] ANY you CAN G[et to] [H]IM, [and I will ...] for the rest to [...] me from Alex[andria ...]. These BOO[ks are] essential to me in my position as LIEU[tenant] COLONEL of IN[fantry] and you will [do me a great favor] by sending [them by hand ...].
Key: key_1864.md
05 Sources
- National Archives, RG 59, Seized Correspondence of Rose O’Neal Greenhow: naId 6925618 (the fragment, one image); naId 1634051 (the clear copy, images 1–2; images 3–6 a different letter and an envelope); naId 1634050, Jordan’s covering note of 23 July 1861.
- National Archives, RG 45, M1091 Subject File of the Confederate States Navy, naId 62017285, image 0484 (the key found on Greenhow, 1864).
- Official Records of the Union and Confederate Armies, Series II, vol. 2, pp. 561–577 (the Greenhow case papers; Jordan to Benjamin, 29 October 1861, pp. 564–565), archive.org.
Files: targets/jordan1861/ (notes, shape-label transcription, the clear copy, decode.py and its controls; the key table is in targets/greenhow1861/key_1864.md). Contributed by WAINUT in pull request #100; reviewed for the site on 27 October 2026.