Ever heard of the Voynich Manuscript? I hadn't, until a little while ago when I came across it while checking out the
Astronomy Picture Of The Day. Following APOD links, I read a rather more detailed description of it
in the Wikipedia. Here's the beginning of that entry, to whet your appetite:
The Voynich manuscript is a mysterious illustrated book of unknown contents, written some 500 years ago by an anonymous author in an unidentified alphabet and unintelligible language.
Over its recorded existence, the Voynich manuscript has been the object of intense study by many professional and amateur cryptographers - including some top American and British codebreakers of World War II fame - who all failed to decipher a single word. This string of egregious failures has turned the Voynich manuscript into the Holy Grail of historical cryptology; but it has also given weight to the theory that the book is nothing but an elaborate hoax - a meaningless sequence of random symbols.
The manuscript is chock-full of mysterious illustrations: drawings of fanciful and unrecognisable plants, often that appear to be parts of several different plants combined into a single chimerical herb; astronomical or astrological diagrams, some of which seem to relate to zodiacal imagery and some which are obscure; weird circular cosmological charts and biological diagrams involving crowned nude women bathing in organ-shaped baths connected by complex networks of pipes. And the text is written in an unknown script, in a "language" that when analysed statistically does show patterns similar to natural language but has so far defied translation by linguests and cryptographers. There doesn't seem to be a lot of doubt about the age of the Voynich manuscript. What's more in doubt is who wrote it and why. Was it a genuine scientific/herbal/alchemical treatise that was written in an unknown or invented script? Or was it written as a hoax to dupe the unwary and impress the foolish? If it was genuine, was it written in a real (but possibly exotic) language in an invented script, or was the language invented as well? Possible authors that have been suggested include John Dee, Roger Bacon, Anthony Ascham and Edward Kelley, among many others.
An hour or so's digging about on the web has turned up some nifty links pertaining to the Voynich manuscript. I'm sure further poking around will find many more (including, no doubt, a vast selection of crackpot tinfoil-hat "theories"). Anyway, here's some good stuff to get you started, if you're interested.
Detailed scans of individual pages of the manuscript - enter "voynich" in the search box and it'll return vast heaps of detailed page scans
A detailed discussion of the manuscript including lots of analysis of its text and illstrations, and comparisons with contemporary manuscripts of known authorship
Wired Magazine, reporting on Gordon Rugg's work suggesting that it is a hoax