The enigmatic Voynich Manuscript, a mysterious book that has frustrated codebreakers and linguists for a century, was penned on 15th-century parchment pages, according to U.S. researchers.
The dating, carried out last year but announced this week, makes the book a century older than scholars had previously thought and quashes some theories about its origin.
Taking its name from the rare book dealer Wilfrid Voynich, who discovered it in 1912 in the Villa Mondragone near Rome, the manuscript, which is about 250 pages long, makes "The Da Vinci Code" pale by comparison.
The book's estimated 250,000 characters are totally alien. Arranged in groups like words and sentences, some resemble Latin letters and Roman numerals; others are unlike any known language.
Moreover, the puzzling handwriting is surrounded by intricately drawn illustrations: plants that can't be identified, astrological symbols, elaborate networks of pipework, and naked ladies dancing or bathing in a strange green liquid.
"Who knows what's being written about in this manuscript. ... Just look at those drawings: Are they botanical? Are they marine organisms? Are they astrological? Nobody knows," said Greg Hodgins, an assistant research scientist and assistant professor in the University of Arizona's department of physics with a joint appointment at Arizona's School of Anthropology.
Working at the NSF-Arizona Accelerator Mass Spectrometry, Hodgins was able to solve one of the many mysteries about the book, nailing down the time when the manuscript's pages were made.
In order to carbon-14 date the book, which is currently kept at the Beinecke Rare Book and Manuscript Library of Yale University and accessible online, Hodgins used four one-sixteenth of an inch by one inch samples from four different pages.
"The four pages were explicitly selected from different sections to try to determine if the book was written over many decades," Hodgins told Discovery News.
Hodgins' team was able to determine that the samples were made between 1404 and 1438 -- quite a narrow range for a radiocarbon measurement.
"Nature worked in our favor. During the early 15th century, radiocarbon levels were changing quite rapidly, so that allowed us to narrow the time frame. Sometimes atmospheric radiocarbon levels remain constant for many decades, even centuries. And in those periods, radiocarbon dating is much less precise," Hodgins said.
According to the researchers, the dating is reliable, since it was repeated four times with independent leaves of parchment.
"It is important to realize that we date when the animal lived, not when the book was made. One can not say how much time elapsed between the death of the animal and when the writer put pen to page. The book was clearly a lot of work and must have taken several years to complete," Hodgins said.
The dating might help in ruling out some hypotheses.
Ever since Wilfrid Voynich made the manuscript public in the hope of having it translated, theories flourished about the book's author and content.
Voynich, which claimed the book had belonged to the 16th-century Habsburg emperor Rudolf II, believed it was authored by Roger Bacon, a 13th-century English friar and scientist -- a theory which carbon dating has put to rest.
Other speculations ranged from the manuscript being the secret work of a religious sect, the only remaining document from a forgotten language, an unbreakable secret code, and the recipe for the "elixir of life."
Several experts also proposed that it was a deliberate hoax, possibly forged by John Dee, an English mathematician and astrologer at Rudolph's court.
Indeed, in 2003 computer scientist Gordon Rugg demonstrated that text resembling that in the book could be generated with a Cardan grille, an encryption device invented around 1550.
"Though I'm not yet 100 percent convinced by the precision of the dating, it's probably reasonably close;" Nick Pelling, the author of "the Curse of the Voynich," told Discovery News.
"By the mid-1920s, it was already apparent to some historians that some of the writing in the manuscript's margins had almost certainly been added in the 15th century, which means that the manuscript could not sensibly have been made after 1500," Pelling added.
"It's a shame that so many people have got stuck on 16th- or even 17th-century theories, particularly the 'hoax' theories, as these have helped deter mainstream historians from getting involved," Pelling said.