The Voynich Ninja

Hi all, I am creating this thread for a theory that is quite distinct from the Modern Forgery Theory, even though it potentially involves foul play by Voynich.

The Book Switch Theory claims that the VMS that we know, Beinecke MS408, is not the book that is mentioned in Marci's letter (hereinafter called "BookA").  There are two variants of this theory:

• H1: When Voynich acquired MS408, Marci's letter was attached to it
  
• H2: It was Voynich who attached Marci's letter to MS408.
  

Here are the factual claims pertinent to this theory, which, AFAIK,  are supported by good evidence.  Because of H2, I do not consider "good" any evidence that depends on anything that Voynich said or wrote, or any material evidence that he could have easily misrepresented, planted, adulterated, or forged.

• F1: Rudolf II once bought from Widemann a set of book for 600 ducats.  Evidence: accounting records found by Rene and others.
  
• F2: In the early 1600s, Barschius had a book (BookA) with figures of plants that were not known in Europe, written in a language that no one could identify.  He wrote about it to Kircher, with a few sample pages.  Kircher did not recognize the language and was intrigued enough to ask for the whole book. Barschius did not send it.  When Barschius died, his friend Marci sent BookA to Kircher.  Evidence: the letters between Kircher, Barschius, Marci, and others, that mention BookA. (While Voynich could have forged Marci's letter, the ensemble of the letters is strong evidence that it is genuine.)
  
• F3: Thousands of Kircher's books ended up in various locations in Rome, under control of the Jesuits.  Evidence: various catalogs and other records collected by Rene and others.
  
• F4: In ~1911, Voynich acquired hundred of books from the Jesuits in Rome. Evidence: accounting records of the Jesuits.
  
• F5: MS408 was written in the 1400s.  Evidence: the C14 date for the vellum and all the stylistic and statistical details. It is very unlikely that a forgery by Voynich or someone could have faked those details so well that it evaded all the tests that were developed and used in the last 100 years.
  

And that seems to be all that we have good evidence for.  Factual claims for which we do not have good evidence include:

• C0: BookA was ever in possession of Rudolf II
  
• C1: MS408 was ever in possession of Rudolf II
  
• C2: Sinapius ever owned MS408.
  
• C3: BookA was one of the books held by Jesuits by 1911.
  
• C4: MS408 was one of the books held by Jesuits by 1911.
  
• C5: Marci's letter was held by the Jesuits by 1911.
  
• C6: Voynich ever got hold of BookA.
  
• C7: Voynich bought MS408 from the Jesuits.
  
• C8: Voynich got Marci's letter from the Jesuits.
  
• C9: Marci's letter was attached to MS408 when Voynich obtained it.
  

In particular, the only evidence for C2 is the signature on f1r; but that is not good evidence, because there is no record of the signature having been seen by anyone before Voynich obtained MS408.

Before we discuss the likelihood of these or other claims, it is worth noting the following features of probabilities:

• P0. There is no certainty anywhere, only probabilities.
  
• P1. There is no such thing as the probability of an event.  A probability is a numeric expression of the strength of one's belief in some claim, and therefore it is inherently subjective and personal. So there is only my probability, your probability, etc.
  
• P2. While Bayes's formula specifies how a rational person should change his probabilities of certain hypotheses on the face of evidence, it depends on his prior probabilities, and on his probabilities that each hypothesis produces observable consequences. Therefore, even after being presented with a ton of supposedly hard evidence, perfectly rational people can still have radically different probabilities for any hypothesis.
  

All the best, --stolfi

The Book Switch Theory (BST) and the Modern Forgery Theory (MFT) have vastly different implications for research on MS408. 

If MFT were true, there would be no point in trying to decipher MS408, since its contents would be gibberish or uninteresting.

In contrast, whether BST is true or not, it would make little difference for our research.  MS408 would continue to be an intriguing document from the 1400s, and our expectations about its contents would not change.  

Except that, if MS408 is not BookA, then we cannot expect to get any clue about the former by tracking down the history of the latter.   In particular, we would not know the whereabouts of MS408 in the early 1600s.

But anyway, assuming that it was in Prague by that time (as we have done so far) still does not give us any clue about its origin or contents...

All the best --stolfi

(09-11-2025, 10:15 AM)Jorge_Stolfi Wrote: You are not allowed to view links. Register or Login to view.If MFT were true, there would be no point in trying to decipher MS408, since its contents would be gibberish or uninteresting.

I agree on most you say, but can't agree on this. Even if the VMS was written in the XVth century its content is probably the same, uninteresting or gibberish (unless it's, say, a copy of some previously lost and important book, who knows). And second, the mistery of how the VMS text was created stays the same, even if it was penned by Voynich (or by anyone else before the computer era). Cheers up 

Just two initial points.

(09-11-2025, 09:40 AM)Jorge_Stolfi Wrote: You are not allowed to view links. Register or Login to view.F4: In ~1911, Voynich acquired hundred of books from the Jesuits in Rome. Evidence: accounting records of the Jesuits.

Fact check: the best guess is 30-ish, as explained here: You are not allowed to view links. Register or Login to view.
There may have been some early prints as well, but I never looked into that. One or two of his catalogues might shed light on this.
It will not have been much, because it just increased the risk for the Jesuits, and Voynich would not have been able to make such a huge profit on them.

(09-11-2025, 09:40 AM)Jorge_Stolfi Wrote: You are not allowed to view links. Register or Login to view.C2: Sinapius ever owned MS408.

(09-11-2025, 09:40 AM)Jorge_Stolfi Wrote: You are not allowed to view links. Register or Login to view.In particular, the only evidence for C2 is the signature on f1r; but that is not good evidence, because there is no record of the signature having been seen by anyone before Voynich obtained MS408.

I have to disagree. An 'ex libris' is generally good evidence that a certain person owned a book.

I can see that this is an important point for your hypothesis that book A is not MS408, as it strongly links MS408 to Prague.

With respect to [C3] and [C4], I guess you will agree that they held one of the two.

(09-11-2025, 09:40 AM)Jorge_Stolfi Wrote: You are not allowed to view links. Register or Login to view.Hi all, I am creating this thread for a theory that is quite distinct from the Modern Forgery Theory, even though it potentially involves foul play by Voynich.

I tried to make a summary from your text with chatgpt and it failed. Maybe the talks here have their own encryption.

(09-11-2025, 12:04 PM)ReneZ Wrote: You are not allowed to view links. Register or Login to view.Fact check: the best guess [Voynich acquired] 30-ish [books from the Jesuits], as explained here: You are not allowed to view links. Register or Login to view.

Thanks for the correction.

Quote:An 'ex libris' is generally good evidence that a certain person owned a book.

But my premise is that "good evidence" excludes anything that Voynich could have easily forged.  And AFAIK there is no record of anyone seeing that signature before Voynich got his hands on MS408. 

I know the argument against that being a forgery: "Voynich could not possibly have known how Sinapius's ex libris looked like at the time".  But that argument depends on trusting Voynich.  He may have known about Sinapius all along, and obtained a copy of his ex-libris early on, but then feigned ignorance.  (In general, "evidence" that a forgery is genuine is much more convincing if the victim discovers it himself, rather than having it pointed out by the forger.)

Quote:I can see that this is an important point for your hypothesis that book A is not MS408, as it strongly links MS408 to Prague.

Indeed it makes "MS408 = BookA" more likely.  But that also provides a strong motivation for Voynich deciding to forge the signature, or to choose MS408 as the replacement for BookA.   Even a gullible millionaire could have wondered whether MS408 was indeed the book mentioned in the letter.   In that case, Voynich would then "discover" the signature "that he had not noticed before"...

Quote:With respect to [C3] and [C4], I guess you will agree that they held one of the two.

I don't see why that would be certain.  Is there good evidence that the "30-ish" books that he acquired from the Jesuits included a book that must have been one of the two?  IIUC, the records of the sale do not say so.  And none of the loose Jesuit ex-libris found in that box at Beinecke fits either MS408 or BookA...

I know that the binding of MS408 resembles that of the books that were re-bound by the Jesuits in the 1800s(?)  How strong is that resemblance?  Could Voynich have forged the binding? (Remember, that was before C14 was even imagined, and AFAIK there has been no C14 test of the glue in the binding yet -- has there been?) 

But even if MS408 was one of the books that were re-bound by the Jesuits, it could have left their hands well before 1911, and reached Voynich in some other way.  He may even have obtained it well before 1911.

If Voynich decided to switch the books (because he had the letter but not BookA, or because he had both but BookA was too obviously not a Bacon original), he would have needed a book that fit the description of BookA in Barschius's letters.  So, if he did not have MS408 already, he may have discreetly hunted around until he found it.  Independently of whether Sinapius's signature is legit or Voynich's forgery.

Again, I don't think that the Book Switch Theory ("MS408 != BookA") is particularly likely.  But I think it remains possible; and my probability is not negligible, because I think that Voynich could have had a $$$trong motivation for doing it, and in my view he was sleazy enough to do it. 

All the best, --stolfi

PS. There is also the possibility that, between 1700 and 1911, someone with access to Kircher's correspondence and/or the Jesuit book collection noticed Marci's letter, and, realizing its huge monetary potential, pilfered it and sold it secretly.   At that point the letter may or may not have been attached to a book;  if it was, that book ("BookX") may or may not have been BookA, and in either case it may or may not have been MS408.

All the best, --stolfi

Both ideas that Jorge has laid out require significant logical and logistical contortions in order to be plausible.

In order for the Sinapius signature to have been faked by Voynich, he would have had to have written it, scraped it away, and then added the "liver of sulfur" reagent to make it legible, damaging the book in the process. Why go to all that trouble and risk? It wouldn't have added to the authenticity of the provenance...an erased/revealed signature has exactly the same evidentiary value as one that was never erased. Same goes for the Marci annotations on f. 1r. How could (and why would) Voynich have faked those, and then made them fade, and then made them legible again, especially since the Marci letter isn't written in Marci's hand but in his secretary's (meaning that Voynich wouldn't have been able to copy Marci's handwriting based on the letter)? 

Is it all possible? Sure. But it is EXTREMELY unlikely. As I have often said, almost anything is possible, but all things are not EQUALLY possible. The simplest and most clear explanation is that both inscriptions are authentic and that the Marci letter is indeed associated with the manuscript.

The lack of external, supporting evidence does not surprise me at all and does not make me suspicious. Nearly every medieval manuscript has holes in its provenance. That is a feature, not a bug, pertaining to all ancient objects. I would be more suspicious if the provenance had no uncertainties at all.

Lisa, thanks for the reply.  You say:

(09-11-2025, 03:35 PM)LisaFaginDavis Wrote: You are not allowed to view links. Register or Login to view.In order for the Sinapius signature to have been faked by Voynich, he would have had to have written it, scraped it away, and then added the "liver of sulfur" reagent to make it legible, damaging the book in the process. Why go to all that trouble and risk?

To prevent any close examination of the signature.  Otherwise, even the forensic tools of the 1920s could have revealed that it was a forgery.

In turn I ask: how come there is no evidence that the signature was there, before Voynich got the book? Neither Barschius nor Marci mention it; and they would surely have noticed it, since it is visible on the photograph taken before the chemicals were applied.   No Jesuit library record mentions it.  And did Voynich himself ever mention it?  IIUC, he made inquiries about "Tepenecz" but did not say why...

And anyway the Book Switch Theory does not require that the signature to be forged by Voynich.  That is just one of the possibilities.

Quote:Same goes for the Marci annotations on f. 1r.

Those few bits of letters resemble Marci's handwriting, but are they positively his?  Maybe those letters were there when Voynich got hold of MS408, but (like the other marginalia) they were not by Marci, but by whoever owned MS408 in the 1600s.

Or maybe they were forged by Voynich, as "evidence" that MS408 was indeed BookA.  Because otherwise there would be absolutely no evidence of that.  Then he smeared that margin with chemicals for the same reason as above, namely to prevent any "forensic" examination of them.

Marci was an important scholar, professor, rector of Charles Univ, etc.  Surely there are many extant samples of Marci's own handwriting out there, that Voynich could have easily have obtained copies of.

Quote:The lack of external, supporting evidence does not surprise me at all and does not make me suspicious. Nearly every medieval manuscript has holes in its provenance.

Yes, and that is a main reason why forgers and scammers thrive in that market...

Quote:I would be more suspicious if the provenance had no uncertainties at all.

Well, the Sinapius signature conveniently being discovered by Voynich on You are not allowed to view links. Register or Login to view. is one of the reasons why I suspect foul play by him...

All the best, --stolfi

While we do not have records for every single step in how Voynich obtained the MS and the Marci letter, this alternative scenario creates an additional list of unexplained steps. Some of them are not only unexplained, but either unlikely or contradicted by other evidence.

Also, it is one thing to consider that Voynich lied about the provenance of some of his books (for good reasons, as we know), planting a fake signature in a genuine book is quite a different step. The question of course has to be: "why?"
It would also have required him to:
- know who was Jacobus de Tepenec
- know how he numbered his books
There is no evidence that he did.

I am not sure if you are aware that there are photos of the first page before Voynich's chemical treatment and after.

The alternative scenario does not explain how and where Voynich acquired the Marci letter. We know it was never included in the carteggio, because each volume has an index listing all letters.
(I am also quite sceptical that this letter presented huge monetary value, but we can leave that aside).

It also does not explain where he got the Voynich MS.

Many things that are easily explained in the normal scenario now become minor or major coincidences.
- He obtained the MS and the other books from the Jesuits in the same year
- The cover of the MS matches the covers of the other books he acquired from the Jesuits, and the books that the Vatican acquired. (This is not hard proof, but it is just one of several things that now become a coincidence, and the regular story has to be preferred).
- The remarkable match between Barschius' description and the Voynich MS now becomes a huge coincidence. (Again, this is not just another 'complete works of Cicero', but a highly unusual book).
- The entry in the Jesuits' catalogue of books sold to the Vatican, which Ruysschaert matched with the Voynich MS, now becomes a loose end. Not impossible, but:
  + it is the only one in the entire list without author or title (check)
  + it is listed as from the 15th century (check)
  + it is listed as being on parchment
  None of this is proof, but the probability that all these things match by coincidence has to be be considered very small.
 
All of this becomes unnecessary when we accept that Voynich bought the MS from the Jesuits with the Marci letter inside. This 'regular' version has to be highly preferred over the alternative one, by an enormous margin.