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The 600-year-old riddle of the Voynich manuscript, explained

The undecipherable medieval manuscript contains a code so complex that no one has been able to crack it.

The Newly Cleaned And Extremely Rare Chained Library At Hereford Cathedral Photo by Christopher Furlong/Getty Images

In 1912, an antiques dealer named Wilfrid Voynich came across a remarkable manuscript. It wasn’t gilded or beautifully illuminated, like the manuscripts with which it was bundled, but it caught his eye nonetheless: It was in code.

It was long — 234 pages — filled with pictures of plants and naked women and what appeared to be astrological diagrams, and line after line of script. And not a word of the script was comprehensible. It wasn’t in any known shorthand or variation of medieval Latin or English or French or any other known language. The entire thing was in code.

“The fact that this was a 13th century manuscript in cipher convinced me that it must be a work of exceptional importance, and to my knowledge the existence of a manuscript of such an early date written entirely in cipher was unknown,” Voynich said. “Two problems presented themselves — the text must be unravelled and the history of the manuscript must be traced.”

To this date, no one has successfully solved either problem.

The text that came to be known as the Voynich manuscript is now housed at Yale, and dozens of medievalists and cryptologists study it every year. Earlier this September, scholar Nicholas Gibbs published an article in the Times Literary Supplement claiming to have cracked the code, only to be pooh-poohed by medievalists across the internet.

Gibbs may have failed to decipher the Voynich manuscript, but he joins a long and illustrious lineage of failures. Cryptologists across the world have tried and failed to decode the Voynich since at least the 17th century, when an alchemist described it as “a certain riddle of the Sphinx.”

Here are the questions posed by that Sphinxian riddle.

Where did the Voynich manuscript come from?

No one knows who wrote the Voynich manuscript or for what purpose, but carbon dating places its origins between 1404 and 1438, despite Voynich’s claim that it was a 13th-century document. As far back as anyone has been able to track discussion of the Voynich manuscript, there is no history of it existing as anything other than a marvelous, indecipherable curiosity. It entered the historical record centuries old and already unreadable.

The first supposed owner of the manuscript is believed to be the Holy Roman Emperor Rudolf II, who allegedly purchased it for 600 gold ducats ($90,000 today) sometime around the beginning of the 17th century, apparently under the belief that the manuscript was the work of the 13th-century English alchemist Roger Bacon. (Rudolf was passionately devoted to alchemy and the occult.) Rudolf, however, seemed to have no luck decoding the manuscript, and it passed from hand to hand until it ended up in Jesuit holdings in Rome, where it would remain hidden until Voynich turned it up 300 years later.

Along the way, the manuscript paused with early cryptologists like the Jesuit polymath Athanasius Kircher, who claimed to have decoded the Egyptian hieroglyphs (he hadn’t), but it remained unsolved. It seems to have consumed the lives of its owners: “To its deciphering he devoted unflagging toil,” wrote the friend of one owner after his death. “He relinquished hope only with his life.”

What’s in the book?

The Voynich manuscript appears to have seven separate sections. Over time, Voynich enthusiasts have given each section a conventional name: botanical, astronomical, cosmological, zodiac, biological, pharmaceutical, and recipes.

The first section is the botanical section, which comprises about half the manuscript and includes pictures of herbs. Some of the herbs appear to be real plants, some of them don’t seem to exist, and a few of them are said to resemble sunflowers, which did not exist in Europe in the 15th century (although this identification has been questioned).

Following the botanical section is the astronomical section, with pictures of the sun, moon, and stars; and then the cosmological section, with pictures of circular geometric designs; and the zodiac section, which features emblems of the zodiac signs.

The biological section is filled with illustrations of naked humans, mostly women, in a series of tubes or baths filled with liquid. In the pharmaceutical section, illustrations of containers are lined up next to illustrations of herbs. And in the end there’s the recipe section, with no illustrations at all: only line after line of that incomprehensible text, each paragraph marked with a star in the margin.

So what do people think it means?

“The whole thing is medical,” wrote alchemist Barchius in 1639, and for most of the Voynich manuscript’s history, that’s been the closest thing there is to a consensus view about it. The plants, according to this interpretation, would be medicinal, and the illustrations of naked women would be anatomical.

But the medical theory is far from the only interpretation that’s emerged over the years.

Early-20th-century philosopher William Romaine Newbold argued that Roger Bacon really had written the whole thing, and that when properly decoded, the manuscript proved that Bacon had used both telescopes and microscopes to anticipate modern germ theory. (The carbon dating of the manuscript that places it in the 15th century means it is impossible the 13th-century Bacon could have written it.)

Military cryptographer William F. Friedman, who helped break Japan’s Purple cipher during World War II, collaborated with his wife and fellow cryptographer Elizebeth for years in an attempt to decode the manuscript. Ultimately, they concluded that cracking the code was impossible, and that “the Voynich MS was an early attempt to construct an artificial or universal language of the a priori type.”

Computer scientist Gordon Rugg thinks the whole thing is a hoax, and that the reason no one can decode the manuscript is that there’s nothing to decode. Botanist Arthur Tucker thinks it depicts Mexican plants. Physicist Andreas Schinner thinks that it was written by “an autistic monk, who subconsciously followed a strange mathematical algorithm in his head.”

Scores of other enthusiastic would-be code breakers over the years have created dozens of other theories, ranging from the vaguely plausible-sounding to the extremely wild.

You may have noticed that few of the theorists I’ve just named are scholars of medieval manuscripts by profession. That’s because most medievalist scholars tend to believe that the Voynich manuscript probably discussed medicine in some way, and also that no theory has generated a decoded text that looks convincing, so there’s no point in speculating much further than that. But for decades, they’ve been patiently debunking wild theory after wild theory about the manuscript.

Into that atmosphere — of endless wild theories, all endlessly debunked — came Nicholas Gibbs.

What’s wrong with the Gibbs theory?

Gibbs, a historical researcher and television writer, argues that the apparent code in the Voynich manuscript is actually a series of Latin abbreviations, with each character standing for an abbreviated word rather than a letter. Once the characters are decoded, he claims, the manuscript becomes clear: It is “an instruction manual for the health and wellbeing of the more well to do women in society.” The recipe section really is a series of recipes for women’s health, he adds, and that would have been clear to everyone if only the manuscript’s original index hadn’t gone missing.

Here’s the problem: The abbreviations Gibbs is proposing don’t render themselves into readable Latin. “They’re not grammatically correct,” Lisa Fagin Davis, executive director of the Medieval Academy of America, told the Atlantic. “It doesn’t result in Latin that makes sense.”

As for the idea that a missing index is the key to everything, Davis says, “This is the piece that really killed it for me.” While there’s some evidence that the manuscript is missing pages, there’s no compelling reason to think that the missing pages were an index.

For Nick Pelling, who runs the Voynich manuscript-focused site Cipher Mysteries, the more pressing issue is that Gibbs’s theory doesn’t offer anything new to the field. Gibbs, he said in a statement to Vox, has essentially cherry-picked from various old theories that have already been debated and debunked without contributing anything new of his own. Worse yet, his theory lacks elegance: It isn’t anchored by a throughline, but instead consists of old worked-over, half-baked theories linked together in a halfhearted narrative. “If enthusiasm could move mountains,” Pelling says of Gibbs, “he’d be in like a shot.”

Many Voynich manuscript scholars and enthusiasts have suggested before Gibbs that the manuscript might be a woman’s health manual, and that part of his theory remains a viable possibility. But it is not a new theory, nor has it been definitively proved, and the coded text of the manuscript remains un-decoded.

Why does anyone care about the Voynich manuscript?

So in the 600 years that the Voynich manuscript has existed, we know of no one who has been able to read a word of it or use it to accomplish anything useful.

Yet people have devoted their lives to studying it. Kings have paid gold for it; alchemists have pored over it; military cryptologists have sweated over it; internet conspiracy theorists have built websites devoted to it. When Umberto Eco visited Yale’s Beinecke Library in 2013, the Voynich manuscript was the only thing he asked to see.

In part, there’s the romantic thrill of the mystery: The Voynich could say anything. It could contain astonishing secrets about the world or human nature or magic. It feels like the beginnings of the plot in a fantasy novel that ends with the person who decodes the Voynich manuscript being declared the rightful ruler of the kingdom.

Pelling argues that the fascination the manuscript wields has less to do with whatever might be hidden in its code than for what we can use it to say about us. When we pore endlessly through its ciphered text, we may or may not be getting all that close to what the scribe who originally penned the manuscript intended to express — but the ideas that we project onto the manuscript can reveal a lot about ourselves and what we hold to be important.

“The evil beauty of the Voynich manuscript,” he says, “is that it holds a mirror up to our souls.”