Appendix II: Italian Cipher

Pages lxix-lxxii

Calendar of State Papers Relating To English Affairs in the Archives of Venice, Volume 2, 1509-1519. Originally published by Her Majesty's Stationery Office, London, 1867.

This free content was digitised by double rekeying and sponsored by the Arts and Humanities Research Council. All rights reserved.


Italian Cipher

History of Italian Cipher.

From the statements of various secretaries preserved in the Archives of the Council of Ten the History of Italian Cipher may be summed up thus.

Until the reign of Sixtus IV. (1471–1484) the cipher still in use was that of Julius Caesar and Augustus, who, when writing secret despatches, made the second or third letter of the alphabet represent the first; and the same sequence was adopted with regard to the others; but as a famous scholar of that period, Leon Battista Alberto, (fn. 1) then wrote a book which divulged the secret, a new school of ciphers and a new sort of cipher sprang up, and amongst its professors the most famous at Venice were the secretaries Zuan Soro, Lodovici, Borgi, Marin, and a renegade Jew named Marco Raphael, who, having apparently betrayed the Signory, made his escape to England, and there found great favour with Henry VIII. in the years 1530 and 1531, not for ciphering, but for writing in favour of the divorce.

Figure 1:

But the father of the science of Venetian cipher was Zuan Soro, of whom the earliest notice with which I am acquainted is dated 8th April 1516, and may be read at p. 293 of the present volume. The passage alludes to his skill in deciphering, and amongst the state papers of Marco Minio, ambassador at Rome, now in my possession, are several ducal missives on parchment written in cipher, the invention of which I do not hesitate to attribute to Zuan Soro. One of these despatches, written throughout in cipher and addressed by the Senate to Minio at Rome, on the 13th August 1519, is endorsed with the monogram which I interpret thus, “Giovanni Battista Soro, Venetus.” The cipher addressed to Minio resembles radically that of which Michiel availed himself in his correspondence with the republic some 35 years later. It consists of capitals and small letters, or signs resembling them, interspersed with numerals &c. To this ciphered despatch no key exists in the Venetian archives.

In June 1529 Soro composed a cipher for the Doge's illegitimate son, who was in great favour at the Porte, and secretly conveyed to the Signory all that he could discover concerning the ambitious projects of Sultan Solyman.

The cipher with which Alvise Griti was furnished on this occasion closely resembles that which Soro used when writing to Minio at Rome on the 13th August, 1519. The live vowels (as seen by the key, preserved amongst the papers of the Council of Ten) are represented in four different ways, thus,—

Figure 2:

Sultan Solyman is represented by a circle, in the centre of which is a dot. The Grand Vizier Ibraim (styled by the historian Sagredo, “the dominator's dominator,”) appears as a crescent; the Emperor resembles an M. No specific cipher is assigned to Henry VIII., or to England, though Gre ece, Turkey, Germany, Italy, Rome, Hungary, Laybach, and the Friuli, have each a peculiar sign of their own as follows:

Figure 3:

Already, on the 18th June 1526, had the Papal legate in Venice borne testimony to the ability of Zuan Soro, by presenting the Signory with ciphered despatches which were written by the ambassador of Charles V. at Rome, and for the comprehension of which recourse was had to Soro, of whom Sanuto remarks that as a decipherer he was unique; and on the following 26th of July, the diarist adds that Soro had deciphered three long letters written by the Imperialists. Moroever, on the 12th of August the Venetian Secretary wrote from Amboise that in France Soro was considered as one inspired (tenuto per Dio), because he had deciphered certain letters, which had been sent for that express purpose from Poitiers to Venice. (fn. 2)

In August 1529 we find Clement VII. complaining to Gasparo Contarini that the Florentines had intercepted his letters, and sent copies of the ciphered parts to Venice that they might be deciphered by Soro, the Pope expressing his belief that “Soro could “decipher any cipher;” but a few days later it was heard at the Vatican that the Venetian secretary had failed to read the ciphered despatches sent thence to the Papal agents in France (fn. 3) The cipher used by Clement VII. was apparently more puzzling than that of Charles V.

In 1544 Soro was dead, and the “Father of Venetian cipher” (as he was styled by one of his juniors in the ducal chancery) had for successors one Zuanne, an engineer, Giovanni Battista de' Lodovici, Zuan Francesco Marin, and Alvise Borgi, these two last being both renowned for their skill in deciphering foreign cipher; and especial mention is made of Marin's having read a most difficult Spanish cipher without any key.

Whilst Soro was in his prime the Venetian diplomatists at foreign courts were each provided with distinct and separate ciphers, but by degrees one single cipher was made to suffice for all the Signory's political agents, an abuse which the Council of Ten at length remedied on the 31st of August 1547, by a decree purporting that “a new cipher was to be made out for each of the Signory's envoys at Rome, to the Emperor, to the King of France, King of the Romans, King of England (Edward VI.), Great Turk (Solyman II.), and also for the secretary at Milan.”

At that period Venice was represented at the Court of Edward VI. by the secretary Jacopo Zambon, none of whose letters exist in the Venetian Archives. The Signory's representatives who succeeded him from 1548 to 1554, were four in number, Bollani, Barbaro, Agostini, and Soranzo; their despatches from England have in like manner perished, so that the earliest specimens of the Venetian cipher, composed expressly and exclusively in 1547 for the use thenceforth of the Signory's envoys accredited to the English Court, are the ciphered passages in the Michiel correspondence.

The task of forming the cipher, as seen by the above-mentioned decree (31 August 1547), was assigned by the Council of Ten to the secretaries Giovanni Battista Ludovici and Alvise Borgi, and they were desired to complete it “within one month at the furthest, and to make a new book of ciphers, stating in detail to whom they consigned them; the book to be kept under lock and key by the secretary charged with the secret register of the Senate in the Secret Chancery,” etc.

All the zealous endeavours made by the “Vice Aggiunto,” Signor Luigi Pasini, to discover the “new book,” compiled three centuries ago, have proved fruitless, but from the writing presented to the Ten by Borgi himself, it may be asserted that the Michiel cipher consists of grain and chaff, the superfluous chaff cipher being introduced for the sole purpose of misleading; and in conclusion, we learn from Borgi that single signs represented syllables and entire words, and that in his time no one had succeeded in forging keys to Venetian cipher of that description.

The photographed letter, (fn. 4) date 18 November 1555, will give the student a clue to the sign representing the title “Serenissimo Principe,” and the two letters of the 28th April 1556, which are almost identical, relate to the execution on that day at Tyburn of Richard Udall and John Throgmorton; so we may suppose the cipher to have revealed some of their confessions, which are known very much to have implicated the Princess Elizabeth. If by any lucky oversight the ambassador had written legibly in one letter, that which was concealed by cipher in the other, some approach might have been made to its entire interpretation; but at any rate, the mere date of the two despatches will interest the biographers of Queen Elizabeth, and the careful collation of them may perhaps elicit some electric spark in confirmation of the Deputy Keeper's well-grounded opinion that the ciphered correspondence of Giovanni Michiel will “throw additional light on the events of the reign of “Queen Mary.” (See Report, p. 5.)

Of the cipher used by the Signory of Venice in the 17th century the accompanying specimen has been lithographed from a despatch written by the Secretary Lorenzo Paulucci in London, narrating the impression produced by the instalment of Oliver Cromwell as Protector. The cipher and decipher are both preserved in the Filza, no. 116, Dispacci Francia; and their reproduction serves to illustrate the history of Venetian cipher and of English popular feeling on the 3rd of January (N.S.) 1654.

Figure 4:Specimen of Venetian Cypher, in the Latter Half of the 17th Century.


  • 1. Leon Battista Alberti was one of the most learned and accomplished men of the fifteenth century, as poet, painter, musician, mathematician, and architect. Concerning him and his works, amongst which, however, no mention is made of cipher, see Operette di Jacopo Morelli, Bibliotecario di S. Marco, vol. ii. pp. 253–72. (Ed. Venice, 1820.)
  • 2. Sanuto Diaries, vols, xli., p. 466., xlii., pp. 163, 342.
  • 3. Letter Book of Gaspar Contarini in St. Mark's Library, 21st May 1528 and .5th November 1529.
  • 4. See p. lix.