I collect historical examples (mostly Italian) of polyphonic substitution cipher in "A Polyphonic Substitution Cipher of the Catholic League (1592-1593)". Now, I noticed a specimen in Devos (1950), possibly related to Spanish ambassador de Spes, and added a reference to it.
Related changes have been made in
"Spanish Ciphers during the Reign of Philip II" and
"Polyphonic Substitution in Italian Numerical Ciphers".
