The Modern Forgery Hypothesis

[Mauro]

But why use XVth century imagery if his aim was to pass it as a lost work of Bacon? That would be quite weird to do, given his expertise with rare books. Why not use XIIIth century imagery?

Well, that would depend on when he nailed down the specifics of his aim, wouldn’t it.
The story considers "even though not consciously aiming to restrict his content to a specific historical period".

But then, why choose Bacon when he knew the imagery he used was ~200 years later? Yet again, given his expertise with rare books, he knew he was going to expose his fraud. Why not choose, say, a lost work of Pico della Mirandola, from the right time period? It's weird, Voynich could not be both intelligent and expert and dumb and ignorant, I think.