An 800-year-old mummy donated to a museum in Italy a century ago has revealed new clues about ancient face tattoos. But the mummy’s origin remains shrouded in mystery.

Some time prior to 1930, the mummy of an adult female was donated to the Museum of Anthropology and Ethnography (MAET) at the University of Turin, with no records of its archaeological context. The mummy recently caught the attention of a team of researchers due to the surprising presence of tattoos on her face.

In a study published in the Journal of Cultural Heritage, the international team of researchers detailed their analysis of the mummy and her tattoos, noting that they were extremely unusual both in their location and in the composition of the ink used to make them. The mummy has straight black hair cropped short and is tightly flexed into a seated position, typical of mummy burials in the Andes. Researchers carbon-dated textile fragments stuck to the body and determined the woman died between A.D. 1215 and 1382.

“On the basis of current evidence — particularly preservation, body placement, associated materials and documents — a South American origin is strongly supported,” study lead author Gianluigi Mangiapane, an anthropologist at the University of Turin, told Live Science in an email.

But while looking closely at the mummy using infrared reflectography, a technique often used to “see through” paint layers of artwork to find older brush strokes, the research team noted a series of unusual tattoos: three lines on the mummy’s right cheek, one line on the left cheek and an S-shape on the right wrist. “Skin marks on the face are rare among the groups of the ancient Andean region and even rarer on the cheeks,” the researchers wrote in the study, and the S-shaped tattoo “is so far unique for the Andean region.”

To identify the ink used to make the tattoos, the researchers used a suite of non-destructive techniques. Although they expected to find evidence of charcoal in the ink, they instead discovered that the unusual ink was made with magnetite, an iron oxide mineral, with traces of the mineral augite. In South America, augite and magnetite can be found together in southern Peru, suggesting a potential homeland for the mummified woman.

“There are a small number of ethnographic accounts from the Americas that describe the use of mineral or earth pigments such as hematite or magnetite for tattooing, and the new study fits quite nicely with those,” Aaron Deter-Wolf, an archaeologist at the Tennessee Division of Archaeology who was not involved in the study, told Live Science by email.