Villains

In the preface to his 1911 play The Fountain, George Calderon says 'my inspiration was certainly not derived from [Shaw's] Widowers’ Houses. Bernard Shaw, like Lloyd George and all those nurtured in the socialism of the early eighties, still believes in the fantastic old Wicked Rich myth. Wren’s jaunty epigram "Villains are a literary invention of the Elizabethan drama inherited from the demonology of the Middle Ages" expresses a truth which has certainly never entered the Shavian head. Mr Shaw’s villainous landlord does not correspond to anything in real life, but is derived straight from the Iagos and Don Johns of the Tudor stage.'

I'm very struck by the line he quotes: ‘Villains are a literary invention of the Elizabethan drama inherited from the demonology of the Middle Ages’, but I can't seem to nail it down. Google is no help. I can't even be sure which Wren Calderon means (surely not this one? And if not him, then whom?). Still, the more I think about it, the more I find myself inclining towards its truth.