I am not convinced by the provenance history of the VMS

[Jorge_Stolfi]

how would you reconcile the Chinese theory with the fact that the VMS Quire 13 (and other folios) contain very strong ressemblances to [European books]

Indeed, many VMS illustrations were clearly "inspired" on those of several other European books, like the Balneis Puteolanis, Oresme's Livre du ciel et du monde, and those "four seasons of life" drawings.  And the dresses and castles are definitely European, and the layout in paragraphs and direction of writing are European, and the vellum and quill pen are characteristically European.

But it is mostly settled that all those details are due to the final copying of the text and figures onto vellum being done in Europe by an European scribe, who obviously used several European books as "inspiration" (and often misunderstood the details).

of Mariano Taccola's De Ingeneis books III and IV, especially the original drawings therein such as the tubes, the bridge scene, etc... As far as we know, Taccola's sketchbook III-IV, of which to our best knowledge no copy has ever been made, was most probably in Siena for the majority of the 15th century.

How do we know that no copy of it was made?  There is no way to tell that by looking at the book itself; and the copying of a book was such an ordinary event that only very rarely and incidentally it was mentioned in surviving documents.  The fact that it was considered a very "rare and valuabe" notebook of a genius must have stoked the demand for copies.

Moreover, I recall mentions on this forum that there is at least another German or Swiss manuscript book with some drawings very similar to Taccola's.  Even with the same crooked perspective and mechanical nonsense.  

the sun-face illustration

Taccola's bridge and streams are just too similar to those on You are not allowed to view links. Register or Login to view. to be mere coincidences.  Either the VMS  Scribed copied from a copy of Taccola's notebook, or both copied from some earlier source.  

But I see that sun image, in particular, as a very weak connection.   

With a quick search I  found several images with that sort of halo (many thin straight lines), including one of Jesus where the halo had also a very similar star-shaped boundary.

Faces on the Moon and Sun had been a common feature of Medieval art for centuries.  While ordinary scribes may have been content with copying the same cartoonish faces that most other scribes used, it would be natural for an artist wannabe like Taccola to draw a more realistic and elaborate one.  Note that the sun drawing in question is not part of a scene, but is clearly an artistic exercise or exploratory drawing -- an attempt to specifically draw a "better" sun with face.

Thus I don't see much of a resemblance between f70r2 and that sun in Taccola's notebook.  Even allowing for gross misunderstandings by the VMS Scribe.

By the way, to my eyes Taccola was a rather mediocre artist, compared to the best of his time.

All the best, --stolfi