Roger Bacon (c. 1220-92) and Geoffrey Chaucer (c. 1343-1400) are often mentioned in connection with cryptography in England.
In the political context, "words of secret signification" were used during the reign of Henry VII by supporters of Perkin Warbeck, who claimed to be Duke of York, the younger son of Edward IV, who mysteriously disappeared in the Tower. In their correspondence, Perkin Warbeck was named "the Merchant of the Ruby" and information "Perkin Warbeck was not able to obtain in Flanders so great succours as he required, to make an attempt on England" was represented as "the Merchant of the Ruby was not able to sell his merchandise in Flanders at the price demanded." (Madden p.175; Arthurson p.149).
Perkin Warbeck was received by many courts and James IV of Scotland even allowed him to marry his own cousin. (A Spanish cipher table used by Ferdinand and Isabella listed "Duke of York" as DCCCCVII beside Margaret of Burgundy and the King of Naples under the chapter "The Pope, the Emperor, Kings, and other persons of the Blood Royal" (Bergenroth p.lxxxiv).) However, none of his military attempts succeeded. When the attempt in Cornwall failed in September 1497, he was captured and was imprisoned in the Tower. He was executed in November 1499. At the same time, the Earl of Warwick was executed for alleged involvement in an escape plot of Perkin Warbeck. In a way, the Earl of Warwick, being son of the Duke of Clarence, brother of Edward IV and Richard III, was more of a threat for Henry VII.
A substitution cipher for Perkin Warbeck is recorded. According to the prosecution record of indictment of Earl of Warwick, Perkin Warbeck in prison somehow delivered to his supporter a certain book called ABC, otherwise called "a Crosse Rowe," and under each letter in the book was written a character or sign so that the supporter could write back to him by those characters or signs. The report recognized that this was for the purpose that "in case any persons unused to such characters should see the said letters, they should not understand their purport." (53rd Report, p.34; Arthurson, p.149, 151)
It appears that Henry VII's government did not use cipher at least until the last years of the reign.
In 1505, England was allied with Spain by the betrothal of Catherine (Katharine) of Aragon, the widow of Prince Arthur, and the Prince of Wales. However, after the death of her mother Isabella, Queen of Castile, in 1504, her father Ferdinand, named by the sole regent of Castile by the will of Isabella but hated by the Castilian nobility, had to struggle for the control of Castile with Archduke Philip, husband of their daughter Juana, who inherited the crown of Castile from her mother. While Henry sent envoys to Spain to make enquiries about a bride for him proposed by Ferdinand, he wanted to approach Archduke Philip.
About March 1505 (Chrimes p.288, Pollard I, p.252), Henry VII sent Anthony Savage to Flanders with instructions to seek advice from Pedro de Ayala, who had been a Spanish ambassador to Scotland and a rival at the English court to Rodrigo Gonzalez de Puebla, an ambassador in London.
In particular, the instruction informed that Emperor Maximilian (called the King of the Romans because he had not been crowned in Rome) had offered his daughter Margaret for Henry's bride and asked a loan from Henry, about which Savage should seek the Spanish ambassador's advice. Henry in particular wanted to know whether the offer of marriage was in earnest and what the marriage portion would be. He further wanted to know the intentions of Archduke Philip and the status and the likely fate of Edmund de la Pole, Earl of Suffolk, a Yorkist claimant to the English throne then held by the Duke of Guelders.
As explained by Bergenroth (p. cviii), the message was thought so important and so delicate that Savage (somehow, Bergenroth refers to "Thomas Savage" and another author, Temperley, refers to "John Savage" (p.338)) was ordered to learn it by heart and the King expected de Ayala to keep his secrets.
According to Arthurson (p.149, 151), this is the first document in record enciphered by the government of Henry VII but Bergenroth, the editor of his source, seems to have a different view.
This document, preserved in the Archives in Simancas, is written in Latin and on paper principally used in Germany and Flanders. Apparently, the original instruction was written in English in plaintext; Savage learnt it by heart as he was instructed and communicated the content orally to de Ayala; and it was de Ayala who enciphered this document. Bergenroth seems to agree with such a story by saying "To confide it to writing seemed too dangerous. It appears, however, that Don Pedro de Ayala, who had not the same reason for keeping the negotiation so entirely secret, insisted on having it put into writing" (p.cviii).
Interestingly, the key to decipher this document is embedded in the document itself in a manner that it appears as though it were a paragraph of the document and a few lines in the postscript in a different cipher indicates where the key of the principal content is to be sought for. The two keys for the postscript (Spanish cipher letters at the time often used two ciphers in a mixed manner) are not extant and Bergenroth had to decipher the whole document.
Bergenroth notes how he could break the cipher of this document. When copying the despatch, he remarked that three lines each contained twenty-one signs, which correspond to the number of the letters of the alphabet that were then in use, whilst the other lines contained generally from twenty-two to twenty-three. Bergenroth suspected that these lines, in all other respects looking exactly like the rest of the writing, concealed the key. He placed the letters A, B, C, and so on over the signs. As it turned out, this provided him the whole key at once (p.cxl).
Catherine of Aragon had to endure many years of neglect in England before fulfillment of the long promised marriage with Henry VIII, who divorced her some twenty years later.
Although Catherine was betrothed to Prince Henry in 1503, neither the English court nor the Spanish court made any effort to expedite the matter, especially after Queen Isabella died in 1504. Both parties were weighing the match against other potential alliances. Ferdinand made peace with France in October 1505, remarrying a niece of Louis XII of France in March 1506. In early 1506, Henry VII in his turn entered into an alliance with Philip of Burgundy, who struggled with Ferdinand for the control of Castile.
When Philip of Burgundy suddenly died in September 1506, many noble suitors coveted the hand of his widow Juana, Queen of Castile in her own right since the death of Isabella. Henry VII was one of them and he thought he might avail himself of Catherine of Aragon, younger sister of Juana.
In March 1507, Ferdinand wrote to Catherine from Italy, where he was settling affairs of his kingdom of Naples, and showed his willingness to pay the marriage portion, after making an excuse for the delay. He told that he sent a letter for the King of England in cipher and that the person who was to decipher it must be a trustworthy person (Bergenroth p.405). While one author (Arthurson p.149) seems to consider this as use of cipher by the English court, it appears that the letter was deciphered by De Puebla, the Spanish ambassador in England, before it was presented to Henry VII, as seen below.
De Puebla enclosed Henry VII's reply of 12 April in his letter in cipher to Ferdinand on 15 April and reported that he received, on the 30th of March, from the Princess of Wales (Catherine), Ferdinand's despatch in cipher of the 15th of March and he showed and explained to the King the despatch which had just been deciphered (Bergenroth p.408).
De Puebla reported that Henry VII was at first very little inclined to consent to the postponement of the payment of the marriage portion; but after long and very unpleasant conversations, he was at last persuaded to do so.
Another letter of the same date, addressed to Almazan, is interesting in that Bergenroth prints the cipher he deciphered.
Catherine wrote to Ferdinand herself on the same day. She explained Ferdinand's letter contributed much to appease the fury of the King of England, which was great, before he consented to the postponement of the payment of the marriage portion. She further stressed what she wrote repeatedly in former letters: because of negligence of Ferdinand and little support from the English court, she was reduced to destitution. She even had to sell her plate of gold and silver, which should be part of her marriage portion.
When she turned to the subject of the prospected marriage between Henry VII and Juana, Queen of Castile, she said she would like to be able to write in cipher. Although she had succeeded in deciphering his letters, she did not dare to make use of cipher in her writing, and much less to confide the ciphering of her letter to any other person. Thus, she wrote in plain Castilian. (Bergenroth p.412, Supplement p.99-104)
On the same day, she also wrote to Almazan that she had deciphered the last despatches without any assistance and she wished she were able to write in cipher. (Bergenroth p.413)
Thus, Catherine could decipher but she was not yet sure of her ciphering skill. In another short letter on the same day, she wrote she had written on the subject in cipher but she thought that her ciphered letter might not be understood and she wrote again in plaintext. (Bergenroth p.413)
Ferdinand, still in Naples, decided to make Catherine his official ambassador and enclosed credentials for her in his letter to the aging and ailing De Puebla to enable her to act in his name (Bergenroth p.416, 417). He explained to De Puebla and Catherine that if Juana could be persuaded to marry at all, her husband should be no other person than the King of England, though such words of the canny King Ferdinand may not be taken at face value.
Catherine reported on 17 July 1507 that she presented the letter of credence to Henry VII and "explained to him clearly that which came in cipher" (Wood p.145) (Bergenroth calendars this as "explained to him the cipher" (Bergenroth p.419). This "cipher" seems to mean the ciphered content, not that Catherine shared the Spanish cipher with the King of England.) Catherine explained Henry VII was satisfied with Ferdinand's intentions and was willing to send an envoy to Spain as soon as Ferdinand returned to Castile and causes of obstruction were cleared.
This letter was written in compliance with the King's wish and was despatched by the King's packet after being read to him. In a more extensive letter dated 18 July, carried by a trusted messenger, she revealed her bitter plight (Wood p.148; Bergenroth p.420).
In advising judicious care in the choice of the ambassador to be sent to England, Catherine went so far as to say "I believe your highness would be frightened at that which I have passed through."
Soon, Catherine felt sufficiently sure of cipher to write in cipher her letter to Ferdinand dated 7 September (Bergenroth p.426). She reported Henry VII's harsh remark that as long as the marriage portion was not paid, he did not think himself and Prince Henry bound by the marriage contract. She complained that De Puebla was more a vassal of the King of England than a servant of Ferdinand and begged her father to deliver her from her painful situation. She also reported that Henry VII was impatient to have an answer respecting his intended marriage.
As to her use of the cipher, Catherine said Ferdinand and Almazan would laugh at her writing in cipher and explained that she took heart to write in cipher, because she did not dare to write the truth in plain writing, as this letter would go by a courier of De Puebla.
In a separate letter to Almazan, who deciphered the letter for Ferdinand, Catherine explained that she did not dare to entrust any other person with the ciphering and excused herself by saying Almazan would find great difficulties in deciphering the letter, and would be obliged rather to guess, than to use the key.
It appears that Catherine used a cipher different from that of the Spanish ambassador, considering Bergenroth noted during the middle of his research that Catherine's cipher was one of the three ciphers that he did not yet understand (memorial sketch p.91). On the other hand, it appears, as noted above, Catherine let De Puebla decipher Ferdinand's letter to Henry VII sent to her. Examination of the manuscript is desired.
Ferdinand sent a new ambassador Fuensalida, empowered to replace De Puebla at his discretion, in 1508 but, as it turned out, the proud ambassador made the situations worse for Catherine. Catherine's appeal to Ferdinand of 9 March 1509 (Bergenroth) was in plaintext, while she wrote in cipher the next letter of 20 March, telling her father she would not believe he looked on her as his daughter unless he punished the ambassador and sent him word to confine himself to the affairs of his embassy and not to meddle in those of her household.
In the end, it was the death of Henry VII in April 1509 that delivered Catherine from her straits. The new King Henry VIII put an end to the prolonged years of procrastination by marrying Catherine of Aragon on 11 June 1509.
In one of her first letters to her father after her marriage, dated 29 July and endorsed 22 July 1509, Catherine spoke of her husband in terms of the deepest affection, which was reciprocated in Henry VIII's letter of a similar tone. An important part of the letter of Catherine, however, was written in a cipher consisting of mysterious symbols and is left undeciphered in Wood (1846). It is regretted that the letter is not included in Bergenroth (1862). (The portion is yet left undeciphered in Brewer (1920).)
The troublemaking Fuensalida was recalled. Ferdinand informed Henry VIII that until a new ambassador, Luis Caroz, arrived in England, Ferdinand would direct all his communications respecting the affairs pending between England and Spain to Catherine and asked him to give her implicit credit. (Bergenroth ii, p.21)
The following letter shows how Catherine acted as a secret channel between the two kings.
Apparently, even after marriage to Henry VIII, Catherine did not give up her cipher to the English ministers and handled cipher for secret communication between the kings.
During the first years of the reign of Henry VIII, Catherine held close communication with her father and advised her husband to strengthen the tie between England and Spain. In 1515, Catherine resigned her position of an ambassador when a worthy ambassador arrived from Spain.
Henry VII was aware of the cipher used by the Spanish ambassador.
In late 1504, England and Spain were both seeking alliance with each other. Spain was at war with France due to partition of the kingdom of Naples and Henry wanted Ferdinand's influence in obtaining the person of Earl of Suffolk, a claimant to the English throne.
Henry wrote to Ferdinand and Isabella about the negotiated treaty of amity and his second marriage with Queen Dowager of Naples. De Puebla promised that his letters should not be sent by land, but by sea because Henry wished that, on no account whatever, should they run the risk of being seen in France (Bergenroth p.343). Cipher was not yet used by the English government.
De Puebla reported in cipher that Henry had some doubts about the offer of the hand of the Queen Dowager of Naples, apart from the need to certify the person and appearance of the bride.
De Puebla advised Ferdinand and Isabella that "whatever your Highnesses may determine to write now, in plain words, and not in cipher, will be productive of good, especially if your Highnesses should reply to the King's letters."
At one time, De Puebla not only gave the deciphered message to Henry VII but also showed him the original letter in cipher.
Still, Ferdinand wrote sensitive matters through Catherine.
In June 1505, general agreement having been reached, Henry VII's envoys, John Stile and two others were sent to Valencia, where the Queen Dowager of Naples was living.
Stile remained in Spain as a resident. He was England's first permanent ambassador to a foreign court (besides two agents at the Papal court in the mid 1480s) (Alexander p.158, Arthurson p.135). When Henry VIII acceded to the throne, Stile was retained in the embassy. .
At the end of Henry VII's reign, John Stile wrote copious political analyses of the political situation in Spain, at times four depatches a week in cipher (Arthurson p.149). Brewer (1920) lists many letters in cipher by John Stile to Henry VIII from as early as 26 April 1509 to 11 February 1518.
Bergenroth calendars one cipher letter by John Stile, dated 21 March 1514 and addressed to Henry VIII, and comments on the cipher used therein: 'The cipher in which this despatch is written is of the rudest and simplest kind imaginable. Every letter has one and not more than one sign, and the words are even separated from each other. Any person, not entirely unaccustomed to reading and writing in cipher, could find out at the first glance such words as "that", "the", "and," &c., and by means of them form in a very short time the whole key of the cipher.' Bergenroth demonstrated his statement by deciphering the letter without a key (Bergenroth p.208). Considering the variety of signs of Spanish ciphers at the time, Stile's cipher (at least this one) was not modeled after the Spanish cipher.
Stile's letters of 1 March and 3 April 1516 are annotated to the effect that a few characters occur at the beginning in a different cipher from that used in the body text, to which no key has been found. The simplest cipher was not the sole cipher used by him.
King Ferdinand died in January 1516. His grandson Charles, son of Queen Juana and late Philip of Burgundy was proclaimed in Flanders as king of Castile and Aragon jointly with Queen Juana. Stile reported in cipher that the states of Castile would not agree to proclaim Charles king during his mother's lifetime and advised his presence in Castile was necessary.
Charles came over to Spain and, in 1518, after negotiations, was accepted by the states of Castile and Aragon. Stile left Spain in May 1518.
Thomas Spinelly was a resident ambassador in the Low Countries and Spain in 1509-1522, during the reigns of Henry VII and Henry VIII. In August 1517, while still in the Low Countries, he delivered his credence to Charles I of Spain and was accepted as a resident ambassador at the court of Spain.
In a letter of 18 January 1515 to Henry VIII, Spinelly said he would write all matters of importance in cipher and would send a key by the Deputy of Calais. Apparently, this did not work, for, on 2 March 1515, he begged the King to have a cipher, explaining that Chievres, Prince Charles' chamberlain, complained of the intelligence he sent. He repeated the request on 23 March to the King and Wolsey. This appears to have had an effect and, on 13 September 1515, he told Wolsey that he would thereafter write in cipher all matters of importance.
According to Mattingly, he used the same cipher throughout his career (Renaissance Diplomacy, p.215).
Spinelly died in Spain in 1522. When reporting the death in a letter of 5 September 1522, King Charles told that he had asked Wolsey's secretary [Thomas Hannibal] to take charge of Spinelly's cipher till the arrival of English ambassadors so that his correspondence with Henry might not be interrupted.
Richard Sampson and Thomas Boleyn were sent to the Spanish court and Sampson was to remain there some years as a resident ambassador, his companion changing from time to time (DNB00). Wolsey sent them a new cipher because Spinelly's had fallen into too many hands.
While use of diplomatic cipher during the reign of Henry VII appears to be limited to the very last years, cipher was already in routine use by several persons in the first years of the reign of Henry VIII.
Ekaterina Domnina, "Ciphers in Early Tudor Diplomacy" in Geheime Post (2015) (updated pdf) focuses on Thomas Spinelly (Thommaso Spinelli in Italian), in particular his private correspondence with his younger brother Leonardo Spinelli in Florence or Rome. It was about 1515 that he introduced cipher in his private correspondence. In a letter of 3 January 1515, he asked his brother to use cipher to keep some information from their other brother, after which they used cipher frequently. (p.184) This was just before Spinelli proposed use of cipher to Henry VIII on 15 January 1515 (see above).
Some time before February 1515, Silvestro Gigli, Bishop of Worcester and resident English ambassador in Rome, from 1514, began using a cipher in his correspondence with the English court. (p.187)
Spinelli brothers' cipher was a homophonic substitution cipher with some nulls (p.185, Fig.1), in which he frankly wrote, apart from private matters, critical comments on diplomatic proceedings and political figures (p.188-190).
Spinelli's private correspondence is in Spinelli Family Papers, among which one letter in cipher is available online (Beinecke Digital Collections).
Arthurson, Ian (1991), 'Espionage & Intelligence from Wars of the Roses to Reformation', Nottingham Medieval Studies, Vol.35, pp.134-154
Houses of Parliament (1892)The Fifty-third Annual Report of the Deputy Keeper of the Public Records, p.34 (Google)
Madden, Frederic (1838), "Documents relating to Perkin Warbeck", Archaeologia, xxvii, p.153 ff. (Internet Archive)
Bergenroth, G.A. (ed.) (1862), Calendar of State Papers, Spain (Google: Vol. 1, Vol. 2, Supplement; British History Online) *The copy at Google lacks pages after p.464 (7 August 1508).
Wood, Mary Anne Everett (ed.) (1846), Letters of Royal and Illustrious Ladies of Great Britain (Internet Archive: Vol. I)
J.S. Brewer (ed.) (1920), Letters and Papers, Foreign and Domestic, Henry VIII, Vol. 1 (2nd ed.) (Internet Archive, British History Online)
Pollard, A.F. (ed.) (1913), The Reign of Henry VII from Contemporary Sources (Internet Archive Vol. I, II, III)
Temperley, Gladys (1917), Henry VII (Internet Archive)
Chrimes, S.B. (1972), Henry VII p.288
Michael Van Cleave Alexander (1981), The first of the Tudors: a study of Henry VII and his reign, p.158
John Galt (1812), The Life and Administration of Cardinal Wolsey (Google)
Garrett Mattingly (1955), Renaissance Diplomacy (Internet Archive)