Could there be more documents written in voynichese ?

[Barbrey]

I think that is more likely.

There is one very odd thing though.

The reverse has a wax seal (just as a stamp - it does not seal anything) with the initials A.G.
This matches (coincidentally?) Aldo Gritti.

That is more than weird. (Best Google for this name).
However, I definitely do not suspect Fabrizio Salani of any involvement in that.
He really hopes that this dates back to Prague and spent some money to have the materials tested.

The parchment has not been dated - at least not that I know - as that would be very expensive.

I believe the seal “stamp” to be a Mason’s seal. I asked the local here  to check it out and they think it very possible. Many masons over the years have individualized their seals. And the VMS is certainly a document that would have interested the masons in any century, just not as far back as the VMS origin as freemasons as known today did not yet exist.