In our Werewolves Podcast, we talk about lycanthropy as a mental illness as opposed to the actual shape shifting of a human being into feral animal operating only on the basest levels of the brain. This was a huge threat to Renaissance high society and showed the fears of allowing the animalism mind to gain precedence over human rational.
John Webster’s The Duchess of Malfi arrived on stage in 1614 and told the story of a man who fell to what medical professors had coined as lycanthropy. Previously thought to be the process through which a man was turned, physically into a beast, even latter day demonoloigists eventually disregarded the idea that a man could sprout a snout, hair and fangs instead agreeing that the process was one carried out purely in the mind of the victim. This idea has even informed our own understanding of such a mental illness and certainly would explain the behaviours of men like Jean Grenier, who we also mention, as an example of this kind of illness.