Bergenroth's Papers on Spanish Ciphers in PRO 31/11/11

Gustave Bergenroth (Wikipedia) was a German-born historian. While studying Tudor history in London, he decided (memorial p.51) to examine papers in the Archivo General de Simancas in Spain, which led to compilation of Calendar of State Papers (the first volume (1862) covering 1485-1509, the second volume (1868) covering 1509-1525).

The work required him to decipher many letters in cipher. For the first volume, he identified twenty keys, though he says some resemble one another and it is difficult to tell whether they are the same keys with some alterations or different ones (Bergenroth p.xiii).

Transcripts he made are preserved in PRO 31/11 in the UK National Archives, of which the present article describes Bergenroth's papers related to cipher in PRO 31/11/11.

For more on the specific ciphers mentioned herein, see another article.

Table of Contents:

Progress of Bergenroth's Deciphering Work

Cipher Keys in the Series

Bergenroth's Report of 4 January 1861


Progress of Bergenroth's Deciphering Work

Early Deciphering Work

He arrived in Simancas in August 1860 (memorial p.52). Early stages of his work in Simancas can be known from his letters to the journal The Athenaeum of 20 September 1860 (p.54), October 1860 (p.61), December 1860 (p.69), and December 1860 (p.78).

One December letter included a transcription of a short paragraph of a despatch from Don Pedro de Ayala in London to the Catholic Monarchs, which had taken a whole week for Bergenroth to decipher (memorial p.76). He had to decipher by himself because he was told by the Archivero [Keeper of the Archives] that cipher keys listed in the catalogue were not extant.

Another December letter included a brief review of Spanish ciphers used at the time (memorial p.79). He wrote of his cryptologic achievement at this stage as follows:

... by a patient comparison of the signs in their different conjunctions, the keys can be discovered. I am already in possession of four complete alphabets, and four more have so much advanced that they begin to become serviceable. However, there remains a whole bundle of despatches, written in the most complicated style, over which I hope, but cannot yet promise, that I shall triumph. I have to-day looked at them, and am glad that already I can read most of them.

Bergenroth's report of 4 January 1861 in PRO 31/11/11 (024.jpg-027jpg) transcribed below, was written shortly after this. Now that he began to succeed in his deciphering work, which was considered impossible before, the Archivero admitted presence of the keys. Feeling that the Archivero was scheming to steal his thunder, Bergenroth tried to secure his priority by sending home the cipher keys he found and asking the recipient to write on it the date he received it. The enclosed keys were received on 12 January 1861 and signed by Thomas Duffus Hardy (PRO31/11/11 028.jpg).

Commissioning of a Calendar of State Papers

The letters published in The Athenaeum were noted by Sir John Romilly, Master of the Rolls, who thought of entrusting Bergenroth with the task of compiling a calendar of state papers in Simancas relating to English history. Such an offer was nothing other than welcome for Bergenroth and Mr. Brewer [John Sherren Brewer?] was sent to Simancas (memorial p.89).

Bergenroth's letter of 31 March 1861 to the Master of the Rolls describes his progress as follows (memorial p.90):

I am happy to inform you that, since I wrote you my former letters, I have discovered a key to new cipher of Doctor de la Puebla, and the key of the cipher of the Duke de Estrada (in English letters generally called Fernanducas). This cipher of De la Puebla is only a small matter, but that of the Duke de Estrada is the most difficult, and at the same time the most important of all, as a greater number of undeciphered despatches are written in it than in any other kind of cipher.

Bergenroth's Codebreaking

The above passage is followed by an explanation of his breakthrough in codebreaking.

When copying an instruction to the Duke, I discovered little dots, like full stops, behind two signs of cipher. As interpunction is never used in cipher of this kind, the dots could only be signs of abbreviation. But even abbreviations (a skilful writer would never have made use of them) offer so many difficulties that they can be employed only on the most common occasions, as, for instance, V. A. for Vuestras Altezas, or n. f. for nuestra fija, or nuestro fijo. From obvious reasons, I decided in favour of 'neustra fija,' and inferred further that the preceding signs must correspond to 'princesa de Gales [Princess of Wales].' The breach was opened, and before three o'clock in the next morning I was in possession of eighty-three signs, representing the letters of the alphabet, and of thirty-three monosyllables, signifying words. The key is far from being complete, but there remain no longer unconquerable difficulties. As I am now able to read the correspondence of the Duke de Estrada, I find that some despatches exist in five, and even in six copies, a circumstance which greatly reduces their number, but to what extent I am not prepared to state.

This is followed by what remains to be discovered.

There remain now, as far as the reign of Henry VII. is concerned, only three systems of cipher which I do not yet understand, viz., the cipher of the Comendador de Haro, the cipher of the Princess of Wales, and a very curious looking letter, which I suspect is an English letter, perhaps from John Stile to the King. Of the two first-named alphabets of cipher I think I have already discovered the weak point; and the supposed English letter, though it looks formidable, does not seem to be written by a master in his art, and is therefore, I think, capable of comparatively easy detection.

Obstacles from the Archivero

Bergenroth no longer needed to rely on cipher keys in the archives, but obviously there were reasons that inspection of the original keys was desirable. Although the Archivero had admitted their presence, he still withheld them from him. As yet, Bergenroth considered he should not make it an issue until he completed the task of copying the despatches in cipher. He was afraid that he might be prevented from copying further despatches (memorial p.92).

Bergenroth's concern became a reality. His letter of 5 April 1861 to the Master of the Rolls (memorial p.95) reported that he was no longer permitted to copy despatches in cipher. He now feared he might be required to give up his copies of cipher to the archives, a thing which he was determined never to accept. He suspected that the Spaniards did not like to see a foreigner succeeding in "deciphering the despatches in cipher without the keys, which he [the Archivero] and they all are unable to read with the keys."

Bergenroth's letter of 30 April 1861 (memorial p.96) reported further obstructions by the Archivero, who ordered Bergenroth's copyist (who was an officer of the Archives) to suppress such portions as he should not think calculated for publication.

Appeal to Madrid

Bergenroth appealed to the authority in Madrid and obtained permission to be shown all the documents including those hitherto kept secret. In return, Bergenroth was to leave copies of his deciphered despatches in the Archives, which the Spanish government promised not to disclose to any person before the English government made use of it. Bergenroth told further details in his letter of 31 May 1861 (memorial p.98-101) and continued to tell that the Archivero first did not accept the order, but soon changed his attitude and they became friends again (memorial p.102).

Now, he had access to not only the despatches in cipher but also the keys preserved in the archives. He felt the difficulties had been more because of the personal jealousy of the Archivero (Don Manuel Garcia) than because of Spanish pride.

Narrative in Print

In the published Calendar, Bergenroth (out of politeness?) attributed the difficulties to "a misunderstanding". (Bergenroth p.xiii)

When I had nearly completed all my keys, doubts arose in the Archives whether I could be permitted to copy the ciphered documents. As I was the only man living who was able to interpret them, the control to be exercised by the Archivero was impossible. The ciphered despatches were actually taken from me, and all my labour seemed destined to be fruitless. I went to Madrid. The result of my appeals to the ministry showed that the whole affair had simply been due to a misunderstanding. The Spanish Government, treating me with the greatest liberality, imposed only one condition; namely, that I should leave copies of all my decipherings and keys in the archives, to which I gladly consented. When I returned to Simancas the ciphered documents were not only restored to me, but another search for keys to the ciphers was made, and resulted in the discovery of one complete key and the fragments of two others.

Subsequent Proceedings

Bergenroth's letter of 20 June 1861 (memorial p.104) reported that his translations of the ciphered despatches were being copied for the Spanish government (memorial p.105).

Bergenroth's letter of 23 June 1861 reported the status as follows.

The despatches in cipher are all copied and deciphered, with the exception of two small letters (the one of them from John Stile to Henry VII.), which I intend to decipher in Barcelona or in London. I am now too fatigued for a work which requires so much concentration of thought as the discovery of the keys to unknown cipher does. Since I wrote my last letter very little has been added to my collection of despatches in cipher; whilst, on the other hand, some more extensive ciphered despatches have disappeared from my list, because they are duplicates of documents which I possessed already. I could not know it before I had deciphered them.

Bergenroth went to Barcelona in September to examine papers in the archives there (memorial p.108). After he returned to England, he visited Paris in the winter of 1861-1862. It appeared that the more he worked, the more need he felt for further search (memorial p.117-118).

In the first volume of the Calendar, Bergenroth summarized his cryptologic achievements as follows:

I discovered the keys to all the ciphers excepting one. It is employed in a short letter of Ferdinand and Isabella to Ferdinand Duke de Estrada, their ambassador in England, dated Segovia, 20th Aug. 1503. It is the only paper extant in that cipher, and it is easy to understand that the shorter the letter is the more difficult is the discovery of the key. I have formed twenty keys; but I will not insist upon that number, as some keys so nearly resemble one another that it is difficult to determine whether they are the same keys, with some alterations, or new ones. In most cases, however, they differ so far that one key does not afford the least help towards finding out another. Some of the keys were of use to me in deciphering page after page; others were useful only for reading a few lines or sentences." (Bergenroth p.xii-xiii)

After Publication of the First Volume of Calendar

After the first volume of the Calendar of State Papers was published, he went to Simancas again. The sensation created by the first volume invoked further obstacles posed by jealous Spanish officials, which Bergenroth overcame as reported in his letters to the Master of the Rolls and Sir Thomas Duffus (memorial p.119 ff.).

While part of the difficulty was due to official regulations (memorial p.163-164) rather than personal jealousy of the Archivero (e.g., memorial p.122, 128), things were made easier for Bergenroth after the Archivero Don Manuel Garcia was replaced, which Bergenroth reported in February 1867 (memorial p.165-166).

Bergenroth had to reexamine the papers because they were incomplete when he had examined them. On the other hand, he found some materials which he had seen before were missing (e.g., memorial p.167). (This may be part of the reason that I could not find online some of the documents calendared by Bergenroth.)

Bergenroth continued to work on unidentified ciphers (April 1864; memorial p.136). As late as November 1867, officers of the Archives were copying his cipher keys and decipherings (memorial p.180).

Cipher Keys in the Series

This section lists cipher-related materials in PRO 31/11/11. (Since the folios are not numbered, the numbering below is merely my file names.)

PRO 31_11_11_001.jpg

Title page.

"Alphabets, Keys to Cyphers, &c."

"Given to Mr. Hardy by Mr Bergenroth"

Below to the left:

"Recd. from Mr. Hardy, 20 May 1868"

"Borrowed from the Record Office

redd. 1 Jan 1877"

PRO 31_11_11_002.jpg

Title page.

"Alfabets, claves, registros, etc."

PRO 31_11_11_003.jpg - 005.jpg

Some code elements.

This corresponds to Puebla's Letter Code.

"Doctor de Puebla"


"hep=Rey de Francia"

"hop=Rey de Inglaterra"





PRO 31_11_11_006.jpg

Cipher alphabet and some code elements (e.g., mul=nuestro).

This corresponds to Estrada's Cipher.

PRO 31_11_11_007.jpg - 008.jpg

Some code elements (e.g., 888=R de Inglaterra).

This corresponds to Puebla's Roman Numeral Code (1495) (Bergenroth/Puebla-4). (Bergenroth occasionally uses Arabic figures for Roman numeral code symbols in his memorandum.)

Titled: "Cifras"

"furadas de las instructiones para de Puebla del 21 Junio y 6 Julio 1496 y de los despachos de Dr Puebla del 13 Junio 1496"

PRO31/11/11 009-012.jpg

Some code elements.

This corresponds to Puebla's Roman Numeral Code (1495) (Bergenroth/Puebla-4)

The title page has "Henry 7 / Simancas / Tratados con Ynglaterra [T.c.Y.] / Legajo 2[?]"

"El Rey y la Reyna"

"Sus altesas recibieron vuestras cartas de ei xx"[?]

PRO31/11/11 013.jpg

(Probably the verso of 012.jpg)

Two blocks of text, with a header "Henry 7."

The following is my provisional transcription.

"E quanto al capitesto del ayuda qui li pedimos qui haga a el papa maruvilladas stan sus altesas como fasta aqui el papa no a escripte cosa alguna cara desto al Rey de Ynglaterra"

"para lo que complis a en bien qui como aqui etiren[?] sus altesas lo de aquies du Yolande tiun por burlis"

PRO31/11/11 014.jpg

Cipher alphabet, corresponding to Puebla's Second Cipher.

PRO31/11/11 015.jpg

Cipher alphabet, corresponding to Puebla's First Cipher.

"1498 / sacadas de la carta de Puebla / 15 Junio 1498"

PRO31/11/11 016.jpg

Cipher alphabet and some code elements (e.g., "batz"=archiduque?, "gav"=R. de Rom, "giv"=Rey Ferd, "gev"=Rey de Franc, "gey"=Rey y, "gay"=la Reyna de Inglat.).

"Londoño y Subprior de Santa Cruz 1498"

Some symbols of the cipher alphabet is similar to those of Puebla's Second Cipher.

PRO31/11/11 017-023.jpg

Some code elements, corresponding to Puebla's Roman Numeral Code.

"1496-1498 Cifras sacadas de los despachos para el Doctor de la Puebla del 21 Jun y 6 Julio 1496 y de las cartas del Doctor del 15 Julio y 19 Julio 1498"

PRO31/11/11 024.jpg-027jpg

Bergenroth's letter of 4 January 1861. See below.

PRO31/11/11 028.jpg

Bergenroth's summary of Puebla's codes and ciphers titled "Correspondence with Doctor Puebla".

In the margin:

"I Received this paper writing[?] on the 12 Janr 1861, enclosed in a letter from Mr G Bergenroth dated Simancas 4 Jan 1861"

"T[homas] Duffus Hardy"

"[two words illegible to me]"

"I.S. Brewer"

The following seven ciphers nos.1-8 (there is no "7") are described.

Bergenroth/Puebla-1 (1488) = Roman Numeral Code (1488)

vii Rey Ferdinand
viii Reyna Isabella
x Infanta Catalina
xi Rey de Inglaterra
xiii lo
xv corte
xvii Rey de Francia
xviii Rey de Romanos
xix Rey de Portugal
xx Bretaña

This is accompanied by a substitution cipher alphabet with homophones for a, s, u.

Bergenroth/Puebla-2 (1491) = Arabic Numeral Cipher (1491)

Also in PRO31/11/11 043.jpg-044.jpg

Roman numbers I to CC of which I can give here only the following examples

III Rey Cattolico
VIII Rey de Francia
XVIII si[?]
xix no
cxxxvi Bretaña
clxxviii Duquesa
Lxxxi tratado
Lxxxix comuniros[?] [overbar and a circle omitted herein]

Bergenroth/Puebla-3 (1494) = Puebla's Letter Code?

la Venecia
her Rey
fav no
hep Rey de Inglaterra
ded Rey de Francia
hap Rey de Romanos
fof las
civ Escocia
bud aqui

Bergenroth/Puebla-4 (1495) = Puebla's Roman Numeral Code (1495)

Roman numbers from I to D, as for inst.
III papa
IV Rey de Romanos
V Rey Catholico
vi, vii El Rey y la Reina
xiii Rey de Francia
xxxvii Navarra
ccccv liga
ccccxx complio
ccccxxvii tiempo

Bergenroth/Puebla-5 (1496) = Puebla's Great Roman Numeral Code (1495)

"Two thousand four hundred Roman numbers, as for inst...."

"at the same time with the following alphabets [=Puebla's First Cipher, numbered "6" by Bergenroth]"


See Bergenroth/Puebla-5 above.


(There is no "7.")

Bergenroth/Puebla-8 (1498)

Cipher alphabet. Somewhat similar to Puebla's Second Cipher.

Also in PRO31/11/11 033.jpg

PRO31/11/11 029.jpg (verso of 028.jpg)

"Correspondence with Pedro de Ayala (Wikipedia) (1498) and Don Martin"

Also in PRO31/11/11 032.jpg and PRO31/11/11 069-072.jpg.

Word "etiam" represented "ll" and "malus" represented "rr" (032.jpg).

Cipher with Ayala and Don Martin

Cipher alphabet.

"To this alphabet belong small words as: nib=Rey de Escocia, pug=yo pu=Vuestras Altezas".

Cipher with Londoño and the Subprior of Santa Cruz

Cipher alphabet and some code elements such as:


gav=Rey de Romanos

giv=Rey Catholico

gey=Rey de Inglat[erra]

gay=Regna de Inglat[erra]

"By means of all the above mentioned ciphers, I have already translated dispatches, as for instance: ..."

Subscribed "Simancas 1st of January 1861 G. Bergenroth".

PRO31/11/11 030.jpg and 031.jpg

Cipher alphabet and some code elements, corresponding to Estrada's Cipher.

The fair copy of 031.jpg is marked "Archivo general de Simancas / Estato. Tratad. con Inglaterra / Leg.2.f.5".

Similar to 006.jpg (somewhat different in u and z).

Code elements include:







rod=Rey de Inglat[erra]

red=Rey de Francia







PRO31/11/11 032.jpg

Ayala's cipher (see 029.jpg).

PRO31/11/11 033.jpg

See Bergenroth/Puebla-8 (1498).

PRO31/11/11 034.jpg

Cipher alphabet

"Archivo general de Simancas / Estado. Tratados con Inglaterra / Leg.2.n.6".

PRO31/11/11 035jpg

Cipher alphabet

"Archivo general de Simancas / Estado. Tratados con Inglat. / Leg.2.n.4".

car=Rey de Inglat

cer=Rey de Romanos

cir=Sus altezas

cor=Principe despaña

cur=Princesa despana

far=Rey de Portugal

fer=Reyna de Portugal



cax=gonzalo Hernandez (?either Bishop Gonzalo Fernández de Heredia, ambassador in Rome (Wikipedia) or Gonzalo Fernández de Córdoba, the Great Captain)

cex=Don Pedro de Ayala

cix=Doctor de la Puebla



PRO31/11/11 036.jpg-042.jpg

"Cifra del Prothonotario Don Pedro de Ayala, annos 1498 a 1500"

Template letter code with entries "aa", "ae", "ai", ..., "bac", "bec", "bic", ..., "niz", "noz", "nuz", of which some are filled with plaintext equivalents:


na=Rey de Francia

no=Rey de Inglaterra

nib=Rey de Escocia (this matches the element of Ayala's cipher of 028.jpg)


PRO31/11/11 043.jpg-044.jpg

"De Puebla 1491"

Template figure code with entries "1", "2", ..., "200", of which some are filled with plaintext equivalents.

See Bergenroth/Puebla-2 (1491) = Arabic Numeral Cipher (1491) above.

PRO31/11/11 045.jpg-051.jpg

"Clave para la cifra de Fernan Duque de Estrada annos 1501 a 1504"

Estrada's letter code.

Template letter code with entries "bac", "bec", "bic", ..., "riz", "roz", "ruz", of which many are filled with plaintext equivalents:


civ como

cov coviene, conveniente

cuv cosa

cax carta

cex correo


PRO31/11/11 052.jpg-058.jpg

"Cifra del Doctor de la Puebla"

Probably Puebla's Letter Code.

Template letter code with entries "aa", "ae", "ai", ..., "bac", "bec", "bic", ..., "liz", "loz", "luz", of which some are filled with plaintext equivalents:

PRO31/11/11 059.jpg

"Archivo general de Simancas Estado Tratados con Ynglaterra Legajo 5.n.18"


PRO31/11/11 060.jpg

A fragmentary ciphertext with partial decipherment "most excell ..."

PRO31/11/11 061.jpg

Cipher alphabet "Cifra de Paris"

PRO31/11/11 062-065.jpg

A copy of a treatise in Spanish?

"Archivo general de Simancas

Estado Tratados con Inglaterra

Legajo 2. n.9"

PRO31/11/11 066-067.jpg

This corresponds to Puebla's Letter Code (as with 003-005.jpg).






hop=Rey de Inglat



PRO31/11/11 068.jpg

Some calculation (multiplication)

PRO31/11/11 069.jpg

Cipher alphabet with a few code elements (generally the same as 029.jpg)

"1498 Pedro de Ayala"

PRO31/11/11 070.jpg-072.jpg

Seem to be working sheets of Ayala's cipher. (The undeciphered text of 072.jpg appears to read something like "ha fecho a r??ra para / descubri?cier?as??sula?o?ielra".)

Bergenroth's Report of 4 January 1861

(Italics are mine. It appears Bergenroth used cipher and transposition to fend off the Archivero's attempts to steal his achievements, but details are not known.)

Simancas, Provincia de
Valladolid, 4th January 1861

Dear Sir,
Excuse me that I trouble you with the following lines. I do not write only to tell you that our old archivero is a ragamuffin. That would not be worth the paper. But I intend to ask a favour of you, that is to preserve the enclosed paper and to write on it the day when you have received it. When, about three months ago, I made up my mind to decipher the dispatches which exist only in cipher, I asked for those bundles which, according to the catalogue, contained keys to ciphers. This archivero, however, told me that there do not exist any such keys and that the compiler of the Index was most probably mistaken. Under such circumstances I had no choice but, either to give up my plan, or to undertake the difficult work of finding out myself the keys by most minutely comparing the different signs in all their conjunctions. I attempted to do it, and all the officers of the archives considered me as little better than a mad man. None of the former students, they told me, had only imagined that such a thing was possible. When I, however, began to succeed, the archivero changed his line of conduct. He ordered that I am not permitted to take any of my copies with me, before they are not copied by an officer of the archives. In consequence, I began to write in cipher. When the archivero saw that he had not succeeded in forcing me first to communicate my copies to him, he made an other order, according to which I am obliged to communicate to him all my keys. Nothing is easier than to elude even this order. I have to do nothing more than to transpose a little the signs and my alphabets will be of no use to any one but to myself.

It is not my intention to make a secret of my discoveries. But, certainly, I do not like in such a way to be deprived of the small honour to be the first discoverer that, I suspect, is the real intention of the archivero. I am the more suspicious with respect to that man, as he told me to day -- when he had seen that I can read cipher -- that the catalogue is right and that such keys do exist. He had the meanness to hide them only that I might not read the papers, written in cipher. As he had succeeded with respect to the Historical Academy in Madrid and with the commissioners of the governments of France and Belgium (cf. memorial p.57, 63), he thought he could as well prevent me from deciphering the papers in question. And why all that? He is jealous. He, although in possession of at least a great portion of the cipher, is not able to read with the help of them and consequently none shall do what is above his capacity.

I do not think that the government shares his ideas. Besides I have excellent introductions to the Don Aureliano Guerra, the Director General of all the archives of Spain, and to other ministers. If I went to Madrid, I think, the archivero would be ordered to change his conduct. But the journey would cost much money and, what is more precious, at least a fortnight of time. The time is so precious, because it seems as though it were earnest to remove the archives from Simancas to Alcalá (cf. memorial p.62). Two officers of Simancas are already sent to the latter place. In consequence of the removal, the archives would perhaps for a year or more remain inaccessible, and you will understand the great interest I have to conclude my researches by that period -- which after all may be many years distant. Who can calculate time in Spain? My plan is now to bear in patience all the arbitrary orders of the archivero as long as possible, only in order to get ahead with my work. At the same time, however, I beg to send you the enclosed alphabets in order to prove the priority of my discovery. Till now, they have not got any of these alphabets. Once more, I beg to excuse me. I would not trouble you, if I know how to secure my right in an other manner. I have sat up night after night till two and three o'clock in the morning for at least three months and do not wish to be deprived of the fruit of my lucubrations, at least not as far as England and Germany is concerned.

Excuse me that I have written so long a letter. I think that the papers, I have already in my possession are of the utmost historical importance / about 120 dispatches, memoirs etc. from 1488-1500 / and that I shall succeed to get much, very much more. Most respectfully, and truly yours very[?] much tired [signed] G Bergenroth


Bergenroth, G.A. (ed.) (1862), Calendar of State Papers, Spain (Google: Vol. 1, Vol. 2, Supplement, Further Supplement; British History Online), in particular, "Remarks on the Ciphered Despatches in the Archives at Simancas", Vol. 1, p.cxxxvii *The copy at Google lacks pages after p.464 (7 August 1508). (Vol. 1 is simply referred to as "Bergenroth" hereinabove.)

Cartwright, William Cornwallis (1870), Gustave Bergenroth: a memorial sketch (Internet Archive, Google) This reprints "Remarks on the Ciphered Despatches in the Archives at Simancas" in the appendix. (Simply "memorial" hereinabove.)

Related Articles:

S. Tomokiyo, Spanish Ciphers during the Reign of Ferdinand and Isabella

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First posted on 19 March 2019. Last modified on 27 March 2019.
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