" To get this right, you’d have to know what codes were doing the round in the eighteenth century, wouldn’t you? Mind you, it ain’t always easy. You’ve heard of the Voynich Manuscript?’
‘No.’
‘A scientific book, at least four hundred years old, written in code. No one’s ever managed to crack that one, not even you modern whizz-kids. "

― , The Apothecary’s House