Secret writings and diplomatic relations: encrypted dispatches from the Roman Curia to Girolamo Casanate (1658-1663).
In the Renaissance, with the flourishing of commercial exchanges and the development of diplomatic relations between states, there was a revival of interest in cryptography. It is in this period that protecting one’s own messages and at the same time intercepting and decrypting those of others becomes an essential necessity for the various European chancelleries and, among these, obviously the pontifical one. The oldest mention of the cipher in pontifical documents dates back to the time of Innocent VIII (1484-1492): the Pope invited the Duke of Milan to write his letters with secret signs known only to the two of them. In a brief from 1493 Alexander VI reports having received an encrypted letter from the king of Spain. However, it was with the pontificate of Leo A Giovanni Ciferator is mentioned in the roles of Pius II (1458-1464), but the first papal secretary of the cipher seems to have been Trifone Bencio, whose activity is attested between 1555 and 1570. With the pontificate of Gregory XIII (1572 -1585) the position was entrusted to Cristoforo Torentino. He followed Giambattista Argenti, who was succeeded by his nephew Matteo. In the history of papal cryptography the two Argenti occupy a prominent place. Both dedicated themselves to their role with extraordinary passion and competence, proud to hold that position of trust and perhaps for this reason intent on passing the secrets of their “art” as a legacy to their family. Both wrote treatises on cryptography and collected and preserved cipher documents and ciphers from their era.