Spanish Codebreaking under Phillip II

The present article describes codebreakers in Spain under Phillip II, focusing on Luis Valle de la Cerda and mentioning three others. Despite the widespread episode of Philip II calling codebreaking "black magic", the Catholic Monarch had a talented codebreaker.

Luis Valle de la Cerda

The most outstanding codebreaker under Philip II is Luis Valle de la Cerda. He is known as a financial reformer, but his codebreaking activities appear to have been comparable to those of famous contemporary codebreakers such as Francois Viete (another article) or Thomas Phelippes (another article). A record of his services styles him as "Luis Valle de la Cerda, del Consejo de Su Majestad y su Contador en el de Cruzada y su Secretario de la Cifra" (Dubet (2000) p.96, n.7).

Date of Birth/Death

Luis Valle de la Cerda was born in Cuenca. There is diverging evidence about his year of birth. There is a record of baptism in Madrid dated 10 January 1552, while the records of services compiled by him and his relatives put his birth in 1560 (Dubet (2000) p.95, 96, citing Ms.994 f.1-4 etc.). From this, Dubet (2000) adopts 1552 as the year of birth, despite the difference in the place (p.13, n.1; the age on p.108; BNE and BnF follow this). Carnicer and Marcos (2005) gives 1559 as the year of his birth (p.244, again citing Ms.994; Navarro Bonilla et al. (2015) p.109 follows this). One source gives ca.1540 (Real Academia).

He died on 25 July 1606 (Dubet (2000) p.117; BNE, BnF, and Carnicer and Marcos p.245, agree with this), though some sources (Navarro Bonilla et al., Real Academia) give 1607.

In the Low Countries

Valle de la Cerda left the university of Salamanca in 1577 (Dubet (2000) p.101) and went to Rome in 1578.

In 1580 or 1581, he went to the Low Countries, where he stayed until 1589. (Dubet (2000) p.102, Carnicer and Marcos p.245) He served in the cipher secretariat of Alessandro Farnese, the Prince of Parma (Wikipedia), who was Spanish Governor General of the Netherlands (1578-1592) and was reconquering towns from the Protestant rebels.

In 1581-1583, during which the army of Farnese took Ninove in 1582 (Motley, The Rise of the Dutch Republic (Google) p.556-557; Debut (2000) p.103), Valle de la Cerda deciphered five letters from the Duke of Anjou to the governor of Cambrai. The cipher had 66 symbols for letters with 18 symbols for multi-letter combinations (BNE Ms.994, f.5-9; Navarro Bonilla et al. (2015) p.110, 114). The duke, brother of Henry III of France, had been offered to become sovereign of the United Provinces in place of Philip II, and arrived in the Low Countries in February 1582 (Wikipedia).

In Tournai, where Farnese had headquarters since he took the town in 1581 (Dubet (2000) p.103), Valle de la Cerda finished writing in April 1583 a tract presented to the king, which was a forerunner to his pamphlet published in 1599: Avisos en materia de estado y guerra, para oprimir rebeliones, y hazer pazes con enemigos armados, o tratar con subditos rebeledes (Notes on Matters of State and War for Suppressing Rebellions and making Peace with Enemies or Dealing with Rebellious Subjects) (Navarro Bonilla et al. (2015) p.110; Juan Eloy Gelabert González (2014), Los avisos de Luis Valle de la Cerda en contexto (1598-1599) (Dialnet) p.36), in which he gave vent to his views as a hardliner against the Dutch revolt and stressed the ingratitude and blindness of the people in Flanders towards the loving and rightful king (Yolanda Rodríguez Pérez (2008), The Dutch Revolt through Spanish Eyes (Google) p.74; see also Navarro Bonilla et al. p.110).

In 1583, Valle de la Cerda was summoned home by Juan de Idiaquez (Wikipedia), Secretary of the Council of State, to tackle cipher despatches concerning Antonio, Prior of Crato (Wikipedia) and claimant to the Portuguese throne. He returned to the Low Countries within the year (BNE Ms.994, f.22-24; Carnicer and Marcos p.244; Navallo et al. p.115).

A letter of 8 October 1585 (Daniel Roxerio to Carlos de Nicles) deciphered by Valle de la Cerda revealed English cooperation to the Dutch (BNE Ms.994, f.26-32; Navallo et al. p.115). For the English, the fall of Antwerp to Farnese in August 1585 as well as the political chaos created by the assassination of the Prince of Orange in 1584 made an intervention inevitable. In December 1585, the Earl of Leicester arrived in Flushing to be Governor-General of the United Provinces (Wikipedia).

At the beginning of 1587, he is recorded to have been in Brussels, where Farnese had moved his headquarters in 1585. This year, he was taken prisoner by the English and was released for a ransom, only because the English did not find out what he was (Dubet (2000) p.103, Navarro Bonilla et al. p.111, Carnicer and Marcos p.245).

Valle de la Cerda longed to return home. When in Turin, Catalina, Duchess of Savoy and Philip II's daughter, gave to Valle de la Cerda on orders of the Duke of Savoy a letter in cipher from Venice. It was from Venetian secretary Marco Otthobon [Marco Ottobon] to ambassador, Juan Mocenigo [Giovanni Mocenigo], dated 27 April 1589. Valle de la Cerda appears to have solved it, but the solution is lost. He returned to Spain in 1589. (BNE Ms.994 f.34-38, Carnicer and Marcos p.245, Navarro Bonilla et al. p.115)

In Spanish Court

Back in Spain, Valle de la Cerda continued to be engaged in cryptanalysis as a cipher secretary of Juan de Idiaquez. (Dubet (2000) p.108-109, Navarro Bonilla et al. p.111, Carnicer and Marcos p.245)

In 1590, Valle de la Cerda was tasked with deciphering intercepted despatches to Longlee, representative of Henry IV of France, the Protestant new King of France. (But Longlee's cipher seems to have been broken in 1587.) (another article; BNE Ms.994 p.64-70; Carnicer and Marcos p.73).

In 1592, Valle de la Cerda deciphered letters concerning the former powerful Secretary of State, Antonio Perez (Wikipedia), who had been persecuted and barely escaped to exile in late 1591 (BNE Ms.18189; Navarro Bonilla et al. p.111, Dubet (2000) p.103, Carnicer and Marcos p.245).

Valle de la Cerda was rewarded with the office of "Contador del Consejo de la Santa Cruzada (Wikipedia)" (keeper of the books of the Council of the Crusade (Wikipedia)) in 1592. (Dubet (2000) p.108-109, Navarro Bonilla et al. p.111, Carnicer and Marcos p.245)

At one time, Valle de la Cerda solved a message in cipher sent by Eufrasia de Guzmán (Real Academia), Princess of Asculi and marchioness of Terranova, lady-in-waiting to the Princess Juana and former lover of none other than Philip II. The message was to tell her rebellious son in prison about his prospects. Valle solved it in a few hours, but had the discretion to write to the King instead of reporting to the Council of Castile. (BNE Ms.994 f.82-98; Navarro Bonilla p.109 places this episode before Valle was appointed the keeper of the books; Carnicer and Marcos p.246 places it in the reign of Philip III, but may be confusing this with some other episode; Ms.994 f.97v, 100v seem to be dated 1 December 1595)

In the New Reign

Philip II died in September 1598 and was succeeded by his son, Philip III.

In March 1599, an old document in cipher was brought to Valle de la Cerda by the Count of Lemos, who deciphered it and found it to concern Archduke Philips' second visit to Spain in 1506 (Wikipedia) (BNE Ms.994 f.186-190).

On 31 March 1599, Valle de la Cerda was given a letter in cipher, presumably as a test of his aptitude, and he solved it within the night. As it turned out, the cipher was merely monoalphabetic substitution! He demonstrated codebreaking in the King's presence. (Navarro Bonilla et al. p.116; cf. Carnicer and Marcos p.439, n.27)

At one time, a secretary of the Council of State handed him letters in a cipher invented by a Milanese, Geronimo Sirtori [Jeronimo Sertori] (Wikipedia). To the secretary's surprise, Valle de la Cerda not only broke the cipher, but also produced a piece of paper showing that he devised the same scheme fifteen years earlier (BNE Ms.994, f.83-90; Navarro Bonilla et al. p.111, 116 as well as Carnicer and Marcos p.245-246 put this episode at 1599, but the record seems to be dated 7 October 1604 on f.90). Although the details of the scheme are not preserved in the archives, according to Nick Pelling's blog ("Girolamo Sirtori Cipher Mystery"), Eloy Caballero came up with an idea that abbreviations are used and have come close to the solution in 2012.

In 1605, Valle de la Cerda deciphered a line segment cipher dating from 1604 about a discovery about techniques in silver mines in the New World, refusing to use the key sent with the ciphertext. His solution was reputed to be "a rare thing of great genius" by the Count of Lemos (Navarro Bonilla et al. p.112, 116; Carnicer and Marcos p.246; see another article).

Other Spanish Codebreakers

As for Spanish codebreakers other than Luis Valle de la Cerda, the following three names are mentioned in many websites (and Navarro Bonilla et al.), but they all seem to be based on Carnicer and Marcos (2005) or Marcos (2014). I have not found anything to add.

Juan Vázquez de Zamora

Juan Vázquez de Zamora started his career at the desk of Antonio Pérez (Wikipedia), Secretary of State. Then, he went to Genoa with Juan de Idiaquez (Wikipedia), who was appointed ambassador. Vasquez de Zamora remained there after the latter left. Juan de Idiaquez, who later became Secretary of State, appreciated his services as a cryptanalyst.

Gaspar de Soto

Gaspar de Soto started his career at the age of fourteen and got familiar with cipher at the desks of the Council of State and the Council of Italy with Secretaries Gaytán and Gabriel de Zayas. (Gabriel de Zayas (Wikipedia) shared the office of Secretary of State with Antonio Perez since 1566, but lost influence after Juan de Idiaquez became Secretary of State in 1579, though he remained in the Council of Italy and the Council of Portugal.)

De Soto stood out in his work during the invasion of Portugal (Wikipedia) (1580-1583). De Soto also worked with ciphers related to Flanders, France, and Germany.

Jerome Gonzalez

Jerome Gonzalez was a decipherer of the Duke of Alba in Flanders. The duke's secretary Francisco de Albornoz highly appreciated his skill with cipher in a letter to Zayas from Maastricht in 1572.


Anne Dubet (2000), "Réformer les finances espagnoles au Siecle d'Or: le projet Valle de la Cerda" (Google), esp. p.95 ff.

Anne Dubet (2000b), "El albitrismo como práctica política: el caso de Luis Valle de la Cerda (1552?-1606)", Cuadernos de Historia Moderna, 2000, no.24, 11-31 (pdf)

Diego Navarro Bonilla and Julio Hernandez-Castro (2015), "Cryptanalysis Skills and Secret Information Practices under Two Monarchs: Secretary Luis Valle de la Cerda, 'Genius of Cipher' (ca. 1559-1607)", Geheime Post p.103-119

Carlos Carnicer and Javier Marcos Rivas (2005), Espias de Felipe II

Javier Marcos Rivas (2014), "La Criptografia y los Servicios Secretos de Felipe II" (pdf)

Real Academia de la Historia

Cristóbal Pérez Pastor (1891), Bibliografía madrileña: ó descripción de las obras impresas en Madrid (siglo XVI) (Google) no.721 ("Valle de la Cerda (Lvis)") p.386-387

Manuscript Sources at National Library, Madrid

Ms. 994

(BNE) This includes a summary of Valle's services and many letters deciphered by him. (There are many missing folios and blank pages.) A printed catalogue is found here (Inventario general de manuscritos de la Biblioteca Nacional, III (897 a 1100) (1957)).

(f.1-4) "Memorial de los servicios que hizo a la Católica Majestad de los Reyes Don Felipe II y don Felipe III, en negocios y materias de estado y guerra en Italia, Flandes y España, Luis Valle de la Cerda, del Consejo de Su Majestad y su Contador en el de Crusada y su Secretario de la Cifra" (Dubet (2000) p.96, n.7)

(f.5-9) Five short letters from Duke of Anjou, January and February 1583, with decipherment and key (homophinic cipher in symbols)

(f.13) A note dated 1917

(f.22-24) Letter about Portugal of 7 August 1583, with decipherment and key (numerical cipher with only one homophone with some code numbers)

(f.26-32) Letter from Daniel Roxerio to Carlos de Nicles about English cooperation with Flanders , 8 October 1585, with decipherment and key (homophonic cipher in numbers, letters, and symbols with code symbols mostly in Roman numerals)

(f.34-38) Letter from Venetian secretary Marco Otthobon [Marco Ottobon] to ambassador, Juan Mocenigo [Giovanni Mocenigo], 27 April 1589; given to Valle in Turin, undeciphered (the solution is "lost")

(f.64-66) Letter from Longlee, representative of Henry IV of France in Spain, 1 April 1590

(f.67-70) Two letters from Longlee to "Monsr. de Wandoma [Womdosma] [i.e., Vendôme], Principe de Bearne" [i.e., Henry IV of France?]

(f.83-86, 90) Record of Valle's solution of text in cipher invented by a Milanese, Geronimo Sertori [Sirtori] (undeciphered)

*A marginal note "Andru deprada" on f.85; an endorsement "Andres de Prada secretario de estado de su Mag^d" on f.88v

*A marginal note "Juan Baptista de Tassis" on f.86; an endorsement "Juan Baptista de Tassis", "..mporta al seru[ici]^o de su Mag^d que se de luego ... abuen receudo" on f.87v

(f.92-98) Letter in cipher of Princess Asculi, reported to the king on 1 December 1595

(f.102-111) Papers about codebreaking demonstration in 1599

a) Valle's letter to the Marquis of Denia (soon Duke of Lerma) about papers ordered to be deciphered, Valencia, 25 April 1599 (f.103, [107])

b) Duke of Lerma to Valle de la Cerda, El Pardo, 28 January 1598 (f.104)

c) Letter in cipher at the end of March 1599 (f.105) (monoalphabetic cipher)

d) Solution (f.106)

e) Valle de la Cerda to Secretary Muriel, key on the verso, 1 April 1599 (f.108)

(f.113-185) Letter from the Indies in line segment cipher with color illustrations; messages of the President of the Indies of 8 May 1605 and 22 September 1605 (f.184)

(f.186-190) Historical letter given by the Count of Lemos in March 1599 and deciphered by Valle de la Cerda, apparently concerning Archduke Philips' second visit to Spain in 1506 (Wikipedia): solution (f.187), copy of the ciphertext (f.188-189), key (f.190)

Ms. 18.189

(BNE) ... Four deciphered letters of Antonio Perez etc. Includes "Extracto de servicios de D. Luis Valle de la Cerda, del Consejo de S.M. y su Secretario de Cifra (h. XIX-XXIv)"

"Extracto de servicios de don Luis Valle de la Cerda que fue del Consejo de Su Majestad y Contador en el de Santa Cruzada y su Secretario de Cifra" (Dubet (2000) p.96, n.7)

Letters encrypted and analyzed by Luis Valle de la Cerda (Navarro Bonilla et al., n.31)

©2020 S.Tomokiyo
First posted on 7 January 2020. Last modified on 13 January 2020.
Cryptiana: Articles on Historical Cryptography
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