People talk about the Voynich manuscript and debate if it were a "fake" or not. But what exactly is the history of fake manuscripts? What would be called a fake and why?

Hi, while you're waiting for a more general answer on book-faking, you may be interested in some of the previous threads on the Voynich manuscript which discuss various reasons for faking:

/u/Owlettt in a lively thread from just a few days ago Is the Voynich manuscript more likely to be a forgery or the product of a forgotten medieval European ethnic group that left no other record?
/u/AncientHistory in What do historians think about the recent "deciphering" of the Voynich manuscript? and with more info in The Voynich Manuscript is sometimes proposed to be an elaborate hoax made during the mid 15th century: were such hoax books common during this period? If so, what was the development process and who was the intended audience?