The Voynich manuscript in the Beinecke Rare Book & Manuscript Library has baffled book collectors, scientists, and even expert linguists of the US Military Intelligence Service for centuries. But it took collaboration between a Yale library and a team of documentary filmmakers to finally crack one of the document’s mysteries.

For the first time since the documents were donated to the Beinecke in 1969, the library worked directly with a documentary filmmaking team in 2009 to re-examine the papers. Beinecke librarians and the makers of “Das Voynich-Rätsel” (“The Voynich Riddle”), an Austrian documentary produced last year and released in English on Feb. 11, were surprised to find that the manuscript is from the 15th century — at least one century older than previously thought.

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“We were happy as a library to have a chance to do new testing on the manuscript,” Beinecke Assistant Curator of Early Modern Books and Manuscripts Kathryn James said, adding that the testing opportunity helped persuade the Beinecke to work directly with producer Andreas Sulzer. The Beinecke and Sulzer share the rights to release the results, she added.

The manuscript consists of 104 pages of parchment featuring graceful script and colored images of exotic plants, intricate astrological charts, and naked nymphs. Since the document was acquired by rare book dealer Wilfrid Voynich in 1912, no expert has been able to decipher the script: it is not written in any language known to man.

Sulzer funded a carbon dating test and pigment analysis of the manuscript at a lab at the University of Arizona. James said recent refinements to carbon dating technology allow scientists to use smaller samples that do not damage the source material. Sulzer originally based the documentary script on his research in the Middle East, which suggested that the manuscript dates to the 17th century. He originally planned to use the test results to prove this hypothesis. But when the lab dated the documents to the 15th century, James said, Sulzer delayed production and sent the script back for rewrite.

“He had to completely rewrite the script at the last minute,” James said.

She added that the carbon test results also “scuppered,” or sunk, her own theory that the manuscript was written in the 16th century by Paracelsians — a sect of physicians who used mineral remedies.

Analysis of the pigments used on the manuscript supported the carbon dating test results, Beinecke Curator of Modern European Books and Manuscripts Kevin Repp said, as all pigments found in the manuscripts were used during the 15th century.

Researchers from within and far beyond the Yale community still do not know what the manuscript says. The Beinecke preserves the manuscript and maintains photographs of every page on its website for reference, James said, but does not try to decipher it. Several e-mails come to the Beinecke every week with people claiming to have deciphered the script, she added, but so far no theory has held up.

Several cult followers of the Voynich manuscripts have created computer algorithms to scour the pages, Repp said. Their programs count symbols, assign a letter to each symbol based on patterns of use and compare the resulting text to known languages, he added. None have succeeded since the script does not resemble any known hypothetical syntax or grammatical structure, Repp said. The script does not even fit patterns that would emerge if a forger tried to select letters at random to produce a meaningless script.

The research findings weren’t the only memorable part of the filmmaking process for Beinecke curators: James said the filming, which took place in fall 2009, was a “comical experience,” adding that the librarians were not used to being hairsprayed or made up, or surrounded by “mountains of equipment.”

“It took us all into new and exciting directions,” she said. “It was one really long week; it seemed to go on forever.”

Repp said he traveled to Austria for the premiere of the film, “The Book that can’t be read,” in summer 2010.

Even though the film has been released and the documentary project is finished for now, there are still opportunities for collaboration among the filmmakers and Yale’s library.

No one has conducted a DNA test on the manuscript to determine the race of cow from which the parchment derives, Repp said. James said such information can be used to locate the document’s origin. Samples taken at the University of Arizona could be used for the test, she said, adding that she anticipates Sulzer will offer to finance the testing sooner or later.

In the wake of the documentary’s release, the manuscript has drawn more interest from researchers and fans of the esoteric archive. James said the Beinecke denied a recent request from artist Trevor Paglen to photograph the manuscript and send the pictures into space as part of the “Artifact Project” tribute to the Voyager probe.

The documentary was not the Beinecke’s first brush with fame: a Beinecke librarian character was recently featured in a Marvel Comic about the Voynich manuscript. The plotline centered on the theft of the manuscript from the Beinecke, and several of the Avengers are shown searching for the documents in Beinecke Plaza.