Trithemius's 'Steganographia'

Around 1499, Abbot Johannes Trithemius of Sponheim wrote 'Steganographia', a book on sending messages through spirits, banned as demonic.

1499 CE · 49.85, 7.72 · status: claim

The sceptical view

In the 1990s researchers showed that the 'spirit magic' hid a working code system.

Sources

1. Wikipedia: Steganographia