How to crack the Manuscript

[ololololo]

Your assumption that it was all done in one go seems to me to be very wrong. It was written piece-by-piece.

I don't really have an opinion on this. However, the idea that a patron would finance a work over a long period of time that he can't even read seems very far-fetched to me. At the very least, you'd expect some explanations in plain language to keep him interested. But as it stands, it doesn't make any sense. There's simply no selling point.

Was there a patron at all?
It seems to me that if the author had the necessary knowledge to write a book and was able to encrypt it securely (or write the text correctly according to his own ideas), then he probably had enough resources to write the book himself. I don't think the author was a poor peasant; he could at least read and write.