Ciphers of Charles IX and Queen Mother, Catherine de Medici

I added a section "Ciphers of Charles IX and Queen Mother, Catherine de Medici" in "French ciphers during the Reigns of Charles IX and Henry III", now renamed from "French ciphers during the Reign of Henry III of France". (I thought separate treatment of the reigns of these brother kings was not necessary.)
As far as I remember, this is the first time I came across ciphers used in the correspondence of Catherine de Medici. The same ciphers were used in letters to the King and Queen Mother as far as these specimens are concerned.
I have been wondering whether Catherine de Medici brought something new to the French cryptography, but these specimens show no such evidence.