One of the most mysterious mediaeval manuscripts, the Voynich manuscript held at Yale University, has been redated almost a century earlier according to the following article:
What interests me is the statement toward the end of the article, that most of the manuscript appears to be written in unrecognizable characters, containing an unrecognizable language, which in turn is mostly gibberish, but containing some legitimate information. The article mentions that it is probably an alchemical code, and that the real meaning of the pages might have been seen by placing a template with holes cut out over the words, revealing the true message.
I own plates of some of the pages of the Voynich manuscript, and I have to concur: the layout, the diagrams, all point to an origin within alchemy. What I disagree with - somewhat strongly in fact - is the notion that mediaeval alchemists would have resorted to the clumsy modern expedient of a "paper template" with holes cut to show the meaningful words. Alchemy's codes are much more complex, as anyone who has ever waded through reading an alchemical text will tell you.
Indeed, alchemy's codes form a kind of "labyrinth in words," and the entry to the labyrinth is, so to speak, the "first secret", given to an initiate by his master. It is a veritable Adriadne's thread by which the initiate is able to negotiate the labyrinth. The secret, the code, in other words, cannot be unlocked without a conceptual key known only to initiates.
The reason for all this secrecy itself is worth some commentary, for there are at least three levels at which alchemical transformation is understood to operate, the least significant being the one that most people think of when they hear the term "alchemy," and that is the transformation or transubstantiation of base metals into gold. The second level is the transmutation of the human soul into an enlightened, god-like soul, and the third, the deepest level, is that of the transmutation of the physical medium itself. For all these reasons, alchemists viewed their science as being fraught with dangers, and hence acted to protect its secrets from potential misuse.
Thus all this talk of secret codes only able to be broken by intiates possessing the key may sound silly, or even impossible, but the fact remains that the Voynich manuscript has defied all attempts of some of the best mathematicians and cryptographers to decipher. It remains a curious manuscript written in an unknown script with an unknown tongue in codes of great sophistication. I have no doubt that, in time, the manuscript will be deciphered and its contents will be known - at least, by someone. But if the diagrams in it are any indicator - one senses a detail of biological knowledge in it that exceeds what is thought to be possible for that day and time - then the manuscript might actually contain knowledge that someone would still want to be kept secret. After all, it has kept those secrets through the centuries.