Solved: the Ciphers in Book III of Trithemius's Steganographia

Book III of Trithemius's Steganographia (written ca. 1500) contains hidden cipher messages within what is ostensibly a work on magic. After almost 500 years these cryptograms have been detected and solved. (Since 1606 it was known that similar ciphers were present in Books I and II.) As a result the Steganographia can no longer be regarded as one of the main early modern demonological treatises but instead stands unambiguously revealed as the first book-length treatment of cryptography in Europe.