The ancient papyrus, shown here after it was cleaned and smoothed, holds medical text possibly written by the Roman physician Galen.

An unreadable wad of ancient papyrus remained tucked away in a Swiss university's collection for nearly 400 years. Conservators have now peeled the pages apart, deciphering the 2,000-year-old text for the first time.

The message? A previously unknown text describing a bizarre theory on hysteria by the Greco-Roman physician Galen (A.D. 130 –210), whose ideas about anatomy and medicine dominated Western science until the Middle Ages.

"We can now say that it's a medical text from late antiquity that describes the phenomenon of 'hysterical apnea,'" Sabine Huebner, a professor of ancient history at the University of Basel, explained in an announcement of the find. "We therefore assume that it is either a text from the Roman physician Galen, or an unknown commentary on his work." [10 of the Most Mysterious Ancient Manuscripts]

The text is thought to have been part of the collection of Basilius Amerbach, a professor of jurisprudence at the University of Basel in the 16th century. Amerbach was famous for having compiled thousands of artworks and cultural objects to fill his "cabinet of curiosities"—ancient coins, woodcuts, illustrated books, manuscripts and even a miniature carving of a unicorn in "unicorn" ivory (really, a walrus tusk). His collection was ultimately bought by the city and the University of Basel in 1661, and became the core of the Kunstmuseum Basel. Amerbach's array of objects went on public display beginning in 1671, sometimes earning it the distinction of the world's oldest municipal art collection.

This particular papyrus had eluded translation for centuries. It had writing on both sides that appeared backward, as if written in a mirror.

A recent investigation by the Basel Digital Humanities Lab used ultraviolet and infrared light to look at the manuscript, showing that it was several layers of papyrus stuck together, perhaps to be reused as bookbinding. After apapyrus restorer separated the individual sheets, the Greek writing could finally be read.

"The majority of papyri are documents such as letters, contracts and receipts," Huebner said. "This is a literary text, however, and they are vastly more valuable."

There are already known texts in which Galen describes hysteria, an affliction that is no longer recognized by doctors but had been diagnosed, predominantly in women, in the past. Galen wasn't convinced by another theory of the era, that hysteria was caused by a "wandering womb." Instead, he thought women became hysterical, and could suffer from "hysterical suffocation," or apnea, when they stopped having intercourse. The condition could make them "apnoic, suffocated or spastic," according to one translation of Galen's text "On the Affected Parts."

It's hardly the first time scholars have tried to recover a Galen text from a recycled manuscript. Earlier this year, particle physicists at a U.S. Department of Energy lab were trying to use high-energy X-rays to reveal the rest of a Galen text hidden on a manuscript that had been repurposed as book of Christian hymns.

Original article on Live Science.