How many people could have written the Voynich?

[Mark Knowles]

You probably noticed that the white Aries and his sheep have a black counterpart. It could be a reference to White and Black Ghibellines and their supporters.

I have not heard of the White and Black Ghibilines, I wonder if you are referring to the White and Black Guelphs. They are, however, Florentine, so I don't quite see how they fit with your Alsatian, Viennese, Slovenian individual.