The Most Secretive Book in History

A bizarre medieval manuscript written in a language no one can read has baffled the world’s best cryptologists, stumped the most powerful code-breaking computers, and been written off as a masterful hoax. Can the hive mind finally unlock its secrets?

The breakthrough, when it finally came, happened in a most unremarkable way. Stephen Bax was in his home office late at night. It was April 2013, and he’d spent the previous 10 months poring over reproductions of a 15th-century manuscript bursting with bizarre drawings: female figures in green baths; astrological symbols; intricate geometric designs; plants that seemed familiar but also just slightly off. Strangest of all—and the reason Bax, a 54-year-old professor of applied linguistics in Bedfordshire, England, had become obsessed—were the 35,000 words in the manuscript. Written in an elaborate, beautiful script, the language has never appeared on any other document, anywhere. Ever.

At his day job at the University of Bedfordshire’s Centre for Research in English Language Learning and Assessment, Bax focuses on English language learning. Decoding ancient manuscripts is not in his purview. But ever since he’d heard about this mysterious book, he’d been fixated on it: scouring the web, talking to scholars, analyzing 14th-century herbal manuscripts at the British Library. And he was fairly confident he’d identified a few words in the document: juniper, cotton, the constellation Taurus. But before he could go public with his findings, he needed more.

On this particular evening, he was looking at the first word of script on a page numbered f3v, which contained an illustration of a plant that looked like hellebore. According to the scheme Bax had worked out, the word spelled out kaur— a word he wasn’t familiar with. So Bax did what anyone would do: He pulled up Google and typed “hellebore” and “kaur.” Then he pressed enter.

The Voynich Manuscript—a soft-bound, 240-page volume—has baffled cryptanalysts, linguists, computer scientists, physicists, historians, and academics since it was rediscovered in the early 20th century. To date, no one has deciphered it, and no one knows why it was made. Experts don’t know what to make of it: is it a cipher, a code, a long-lost language?

There’s been plenty of speculation, both inside and outside academia. Over the past century, the case of the Voynich has been cracked and debunked, cracked and debunked again, and even—rather convincingly!—exposed as a hoax. Even the book’s acquisition is a mystery.

The story starts with a London-based book dealer named Wilfrid Voynich, who discovered the book in 1912. From the beginning, Voynich was evasive about how he acquired the tome—he claimed he’d been sworn to secrecy about its origin, and the story he recounted changed often. In the one he told most frequently, he’d been at “an ancient castle in Southern Europe” when he found this “ugly duckling” buried in a “most remarkable collection of precious illuminated manuscripts.”

For a book dealer, it was like stumbling onto treasure. Back in London he dubbed his acquisition the “Roger Bacon cipher,” after the 13th-century English monk and scientist, and put it up for sale. A letter that came with the book suggested Bacon was the author; whether Voynich actually believed it, or whether he simply believed that associating the book with Bacon would help him fetch a higher resale price, is unclear.

“I think he’s best compared to a used car dealer,” says René Zandbergen, a space scientist who lives near Darmstadt, Germany, and runs a Voynich website in his spare time. “He was selling secondhand books and making sure that this [one] would get the best price he could get.”

By 1919, Voynich had sent copies of the manuscript to experts who might be able to determine the book’s purpose. One of those men was William Romaine Newbold, a philosophy professor at the University of Pennsylvania. Taking a magnifying glass to the text, Newbold noticed strange irregularities at the edges of the letters. He believed the tiny lines were Greek shorthand—and that each letter contained as many as 10 of them. The letters themselves, he thought, were meaningless. But the shorthand might hold the key to decoding the manuscript.

Newbold converted the script to letters, and then anagrammed until he found readable text. His translation seemed to corroborate Voynich’s hunch: The manuscript had belonged to Bacon, and the illustrations showed that the friar scientist had made incredible discoveries. One drawing, Newbold believed, showed the spiral-shaped Andromeda Galaxy—hundreds of years before astronomers would discern the galaxy’s structure—and others showed cells. Newbold surmised that this meant Bacon would have had to have invented both the telescope and the microscope. If his contemporaries had known what he was up to, Newbold theorized, they’d have accused him of working with the devil. That’s why he had to use a cipher to record his findings.

Word of the manuscript spread. In 1931, John M. Manly, a Chaucer expert at the University of Chicago—who’d been “dabbling” with the manuscript for years—published a paper that erased Newbold’s findings: Those irregularities at the edge of the letters weren’t shorthand; they were simply cracks in the ink.

But Manly’s discovery only fueled the public’s desire to understand the mysterious manuscript. Before long, experts from every field had joined the effort: Renaissance art historians, herbalists, lawyers, British intelligence, and teams of amateurs. Even William Friedman, who had led the team that solved Japan’s “unbreakable” Purple cipher in World War II and had since become head cryptanalyst at the National Security Agency, took a crack at it. He never got close to solving it.

There are lots of questions surrounding the Voynich manuscript, but the most essential is: What is it? Because of the numerous illustrations of plants, many believe the manuscript may be an herbalist’s textbook, written in some kind of cipher or code—and the two terms are not synonymous. Technically, a code can only be cracked if you have—or can figure out—the guide to that code. A cipher is a more flexible algorithm, say, where one letter is substituted for another. (For a simple example, a = p.)

There are a number of ways to crack a cipher, but one common technique is frequency analysis. You count all the characters, find which are most common, and match that against a similar pattern in a known language. More elaborate ciphers might require different kinds of frequency analysis or other mathematical methods.

What Friedman saw—and what makes the Voynich so compelling—is that the text isn’t random. There are clear patterns. “There’s a set number of characters, an ‘alphabet’ with letters that repeat,” says Elonka Dunin, a Nashville video game designer and author of The Mammoth Book of Secret Codes and Cryptograms who created her own page-for-page replica of the Voynich (just for fun!). But she has doubts that the book is a cipher. “Ciphers back then were just not that sophisticated. With modern computers, we can crack these things quite quickly.” But a computer hasn’t yet, and that’s a red flag.

Back in 1959, Friedman came to the same conclusion. Never able to crack the code, he believed the text was “an early attempt to construct an artificial or universal language of the a priori type”—in other words, a language made up from scratch. Some agree. But others think the words might be a language of another kind. Which brings us to Bax.

It took a split second for Bax's Google results to confirm that kaur was a name in Indian herbal guides for black hellebore. It was a match! “I almost jumped up and down,” he says. “All of the months and months of work were starting to show some cracks in the armor of the manuscript.” That night, he couldn’t sleep. He kept going over the research in his head, expecting to come up with a mistake.

If he was right—if certain words were identifiable as plant names—then his findings agreed with Friedman: The book was not a cipher. But unlike Friedman, Bax didn’t think the language was made up. He was convinced that it resembled a natural language. He’s not alone. One study of the Voynich, published in 2013 by Marcelo Montemurro and Damián Zanette, noted that statistical analysis of the manuscript showed that the text has certain organizational structures comparable to known languages. The most commonly used words are relatively simple constructions (think the or a), while more infrequent words, those that might be used to convey specific concepts, have structural similarities, the way many verbs and nouns do in other languages.

However, there are quirks. In most languages, certain word combinations recur frequently; but according to Zandbergen, that rarely happens in the Voynich. The words tend to have a prefix, a root, and a suffix, and while some have all three, others have only one or two. So you can get words that combine just a prefix and a suffix—uning, for example. Further, there are no two-letter words or words with more than 10 characters, which is strange for a European language. That’s enough to put some people off the idea that it could be a natural language.

When Bax started working with the text, he treated it like Egyptian hieroglyphics. He borrowed an approach used by Thomas Young and Jean-François Champollion, who in 1822 used the proper names of pharaohs—easy to identify because they were marked with a special outline—to work backward, assigning sound values to the symbols and then extrapolating other words from these. This was something that, Bax says, no one had systematically attempted on the Voynich.

The first proper name Bax identified was a word next to an illustration of a group of stars resembling Pleiades. “People before us suggested that that particular word is probably related to Taurus,” he says. “If you assume it says Taurus, the first sound must be a ta, or somewhere in that region—ta, da, Taurus, Daurus.” The process seems insanely daunting at first: “On the basis of one word alone, that’s just complete imagination,” he says. “But then you take that possible ta sound and you look at other possible proper nouns through the manuscript and see if you can see a pattern emerging.”

Bax worked for a year and a half, deciphering crumbs of letter-sound correspondences. Eight months after he confirmed hellebore, he published a paper online detailing his method. He cautiously announced the “provisional and partial” decoding of 10 words, including juniper, hellebore, coriander, nigella sativa, Centaurea, and the constellation Taurus.

"University of Bedfordshire professor cracks code to mysterious 15th-century Voynich manuscript," the local paper blared. Quickly, news organizations around the world joined in.

Nothing major happens in the long saga of the Voynich without media hype. The last time it had happened, in 2004, a British computer scientist named Gordon Rugg had published a paper showing that the whole thing might be an elaborate hoax created expressly to separate a wealthy buyer from a lot of money. And where there’s media controversy, there’s contention among Voynich obsessives. Rugg says his theory was like “someone grabbing the football and walking off the pitch in the middle of a really fun game.”

Bax’s proclamation came with its share of controversy, too. People in the Voynich world have seen a lot of so-called cracks over the years, none of which have panned out, so when the news stories appeared on Bax’s paper, Dunin, the video game designer, just laughed. “The media just picks it up uncritically and says, ‘He must have solved it.’ He didn’t,” she says. “He’s saying, ‘I saw this, and this looked intriguing,’ and that’s perfectly valid. But it’s not a crack.” Others criticized his methods: Some had issues with the idea that the first word on a page is a plant name, because many of those words start with one of only two letters. Some found it weird that his translation has three different characters that stand for the letter r.

Bax doesn’t claim he’s cracked the code. “I’m prepared to see that some of the interpretations I’ve suggested are revised or even thrown out,” he says. “That’s the way you make progress on something like this. But I’m pretty convinced that a lot of it is solid.”

He’s determined to prove it, by stoking more dialogue within the obsessive community. In addition to the Voynich Wikipedia page, there’s an entire Wiki devoted to the book’s oddities and the efforts to crack it. Mailing lists started in the early 1990s are still going strong. Reddit, too, has taken an interest, and when Bax did an AMA after publishing his paper, it got 100,000 pageviews. Bax himself has set up a website to document his efforts. He actively encourages participation, fielding comments from visitors eager to help him decode the book.

One such volunteer is Milan-based Marco Ponzi, who had been researching Tarot card history when he found Bax’s paper. Ponzi began commenting on Bax’s website, suggesting there might be parallels between certain diagrams in the volume and images that appear in the Tarot. “Since Stephen is so rigorous and so kind, I feel encouraged to propose new ideas,” he says. “I don’t know if I have contributed anything really useful, but it is very fun.”

“Marco is bringing his expertise in medieval art, iconography, and Italian manuscripts—which I don’t have,” says Bax. “This is one of the beauties of doing it through the web.” Indeed, it’s become an international collaboration. Bax has asked other readers to add their own observations in the comments section, and spends a lot of time responding to queries and participating in the discussion. In the future, he hopes to host conferences and seminars about the book, and to set up a site where he can crowdsource efforts to decode other Voynich sections. If the method works, he expects that the manuscript could be decoded within four years.

What will be revealed when—and if— it is? Bax believes the manuscript is a treatise on the natural world, written in a script invented to record a previously unwritten language or dialect—possibly a Near Eastern one—created by a small community that later disappeared. “If it did turn out to be from a group of people who have disappeared,” he says, “it could unlock a whole area of a particular country or a group that is completely unknown to us.”

Other theories put forth that the secrets locked inside the Voynich’s vellum pages could reveal a coming apocalypse—or merely the details of medieval hygiene. Some people think the script could be the observations of a traveler who was trying to learn a language like Arabic or Chinese, or a stream-of-consciousness recording of someone in a trance. The most bizarre theories involve aliens or a long-lost underground race of lizard people.

It’s possible that the book will never tell us anything. To Zandbergen, whether it has huge secrets to reveal doesn’t matter at all. He just wants to know why the book was written. Whether it’s the work of a hoaxer, an herbalist, or a lizard person, the Voynich is important all the same. “It’s still a manuscript from the 15th century. It has historical value,” he says. But until the truth is revealed—and probably even after—people will keep trying to crack the Voynich. After all, who doesn’t love a good puzzle.