ROME (AP) — A Vatican researcher claims a nearly invisible text on the Shroud of Turin proves the authenticity of the artifact revered as Jesus' burial cloth.

The claim made in a new book by historian Barbara Frale drew immediate skepticism from some scientists, who maintain the shroud is a medieval forgery.

Frale, a researcher at the Vatican archives, said Friday that she used computers to enhance images of faintly written words in Greek, Latin and Aramaic scattered across the shroud.

She asserts the words include the name "Jesus Nazarene" in Greek, proving the text could not be of medieval origin because no Christian at the time, even a forger, would have labeled Jesus a Nazarene without referring to his divinity.

The shroud bears the figure of a crucified man, complete with blood seeping out of nailed hands and feet, and believers say Christ's image was recorded on the linen fibers at the time of his resurrection.

The fragile artifact, owned by the Vatican, is kept locked in a special protective chamber in Turin's cathedral and is rarely shown.

Skeptics point out that radiocarbon dating conducted in 1988 determined it was made in the 13th or 14th century.

While faint letters scattered around the face on the shroud were seen decades ago, serious researchers dismissed them due to the test's results, Frale told The Associated Press.

But when she cut out the words from photos of the shroud and showed them to experts they concurred the writing style was typical of the Middle East in the first century — Jesus' time.

She believes the text was written on a document by a clerk and glued to the shroud over the face so the body could be identified by relatives and buried properly. Metals in the ink used at the time may have allowed the writing to transfer to the linen, Frale claimed.

Frale claimed the text also partially confirms the Gospels' account of Jesus' final moments. A fragment in Greek that can be read as "removed at the ninth hour" may refer to Christ's time of death reported in the holy texts, she said.

On an enhanced image studied by Frale, at least seven words can be seen, fragmented and scattered on and around Jesus' face, crisscrossing the cloth vertically and horizontally. One short sequence of Aramaic letters has not been translated. Another Latin fragment — "iber" — may refer to Emperor Tiberius, who reigned at the time of Jesus' crucifixion, Frale said.

"I tried to be objective and leave religious issue aside," Frale told The AP. "What I studied was an ancient document that certifies the execution of a man, in a specific time and place."

Frale is noted in Italy for her research on the medieval order of the Knights Templar and her discovery of unpublished documents on the group in the Vatican's archives.

Earlier this year she published a study claiming the Templars at one time had the shroud in their possession. That raised eyebrows because the order was abolished in the early 14th century and the shroud is first recorded in history around 1360 in the hands of a French knight.

But her latest book, titled "The Shroud of Jesus Nazarene" in Italian, raised even doubts among some experts.

"People work on grainy photos and think they see things," said Antonio Lombatti, a church historian who has written books about the shroud. "It's all the result of imagination and computer software."

Lombatti said that artifacts bearing Greek and Aramaic texts were found in Jewish burials from the first century, but the use of Latin is unheard of.

He also rejected the idea that authorities would officially return the body of a crucified man to relatives after filling out some paperwork. Victims of the most cruel punishment used by the Romans would usually be left on the cross or were disposed of in a dump to add to the execution's deterring effect.

Lombatti said "the message was that you won't even have a tomb to cry over."

Unusual sightings in the shroud are common and are often proved false, said Luigi Garlaschelli, a professor of chemistry at the University of Pavia.

Garlaschelli recently led a team of experts that reproduced the shroud using materials and methods that were available in the 14th century, proof, they said, that it could have been made by a human hand in the Middle Ages.

Decades ago entire studies were published on coins that were purportedly seen on Jesus' closed eyes, but when high-definition images were taken during a 2002 restoration the artifacts were nowhere to be seen and the theory was dropped, Garlaschelli said.

He said any theory about ink and metals would have to checked by analysis of the shroud itself.