Republished copy of Daniel Bourdeau’s Unsolved Historical Ciphers, released under CC BY 4.0. Text unchanged; hosted by JIC alongside its translations; not an official copy by the author · View the original ↗
UPONSATERDAYBEINGOURFIFTEENTHOFTHEPRESENTE · a=U b=P c=O d=N e=S f=A g=T h=E

England → William Boswell · simple substitution in invented signs · December 1627

Sir Ralph Boswell to his cousin William Boswell, 15 December 1627

TNA State Papers 106/5 ff. 20–21 (DECODE R413), catalogued as a ciphered letter of King Charles I to William Boswell, 1628, with nothing known of its content. Mark Woodard recovered the key and deciphered it on DECODE in 2021. His key was checked against the ciphertext and applied here; three signs he left open are filled, and the sender and the date are identified from the back of the letter.

Daniel Bourdeau · posted · updated

Method: read with known key · Extent: complete

Summary. The catalogue entry (no. 63) described ten lines of “esoteric symbols” from King Charles I to William Boswell. The DECODE record already holds a decipherment by Mark Woodard of Furman University, uploaded on 9 November 2021 and made with CrypTool 2’s monoalphabetic analyzer. It is a simple substitution, one invented sign per letter, and the text is English court news: Buckingham has come back from Plymouth to Whitehall, is confident of the King, and does not fear his enemies in the Commons. Aligning Woodard’s transcription with his plaintext shows every sign standing for one letter without exception. Of his three open signs, one is s and one stands for a whole word, probably “part”. A pair of signs in the third line is not deciphered. The endorsement reads “S[i]r Ra: Boswele. 24 Jan. 1627”, so the writer is Sir Ralph Boswell, a kinsman (“my … Cosin”), not the King. “Saturday, our fifteenth of the present” then fixes the letter to 15 December 1627.
Three lines of invented cipher signs written without word division
Lines 1–3 of the cipher, turned to the writer’s orientation: Upon Saterday being our fifteenth of the presente… Image: The National Archives, Kew, SP 106/5 ff. 20–21, via DECODE R413.

01 The document

Page one has ten numbered lines of signs, written across the sheet, with no word division. Page two carries the address, To my Especiall & most Esteemed Cosin William Boswell Esq., a seal, and the endorsement S[i]r Ra: Boswele. 24 Jan. 1627, that is 1627/8. Below it, in the same hand, is a list of eight topics: Hopyan, Pettyt, the Court of Wards, Yorkshire lands, Sir Anthony Aucher, Morgan, one unread, and the Earl of Dorset. The same page has a tally of every cipher sign with the numbers of the lines it occurs in. That is the working sheet of whoever took the letter apart, either Boswell or a clerk. DECODE’s own note already doubted that the King wrote it; its author and 1628 date are catalogue placeholders.

02 The key

Woodard transcribed the signs as letters a–x. Aligned with his plaintext, all 442 signs map consistently:

a U/V  b P  c O  d N  e S  f A  g T  h E  i R  j D  k Y  l B
m I    n F  o H  q G  r K  s M  t C  u L  v W
p S (two uses, read here)    w ? (two uses)    x ? (one use)

Letters with no sign in the text are j, q, x, z. The writer confuses P and F (ofinion), puts H for F (heares = feares), and has an extra S in maskinge and L for R in loldes.

03 The decipherment

Upon Saterday, being our fifteenth of the presente, our[s] greate Duke returned from Plimmouth to Whitehall, contrary to the opinion of very many who conceaued he [​w x] would not haue appeard heere before he had heard how the pulse of the Parlamente had gone. But being confident of the King’s fauour, [f]eares not the many enemies that he hath in the Lower House, especially hauing so greate a party in the Higher House by reason of the Bishops and the new Lords, which for the most [part] are(d) of his owne makinge; and to take away the ill opini[on] of such lordes …

The text breaks off mid-sentence at the end of line 10. The “new Lords” are the peers Buckingham had had created, the bishops were largely of his party, and the Parliament being discussed that winter was summoned by writs of 30 January 1628.

04 Date

In the Julian calendar the 15th fell on a Saturday in December 1627 and March 1628; 15 January 1628 was a Tuesday. With receipt endorsed on 24 January 1627/8, the Saturday is 15 December 1627. Buckingham had come back by way of Plymouth from the failed Île de Ré expedition in November 1627. The date of his arrival at Whitehall was not checked against a printed source here.

05 What remains uncertain

06 Sources

Notes, transcription and profile: targets/boswell1628/ in the repository.