Egyptian mummy gives up embalming secrets

For thousands of years, ancient Egyptians carefully mummified the bodies of their dead in readiness for the afterlife. But the origins of the ritual are still shrouded in mystery.

A team of chemists and Egyptologists has now carried out the first chemical analysis of embalming compounds from an intact prehistoric mummy, kept at the Egyptian Museum in Turin. The researchers dated it to 3700–3500 B.C., making it the oldest-known embalmed body.

The results show that people prepared the Turin mummy centuries before the pharaohs unified the region in about 3100 B.C. to form ancient Egypt. The team’s analysis suggests that long before the founding of what was arguably the world’s first nation-state, the people who lived there shared common cultural practices and imported embalming ingredients from distant lands (J. Archaeol. Sci. 2018, DOI: 10.1016/j.jas.2018.07.011).

Mummification in ancient Egypt involved removing the corpse’s internal organs, desiccating the body with a mixture of salts, and then wrapping it in cloth soaked in a balm of plant extracts, oils, and resins. Egyptologists thought the practice began around 2600–2500 B.C., although several studies in the past decade have pushed back that date. Older mummies from the pre-pharaonic period were thought to be naturally preserved by being buried in dry desert sand, without the help of chemical embalming.

In the new study, researchers took samples from textiles attached to the Turin mummy’s right wrist and back and used several gas chromatography/mass spectrometry (GC/MS) techniques to identify a range of embalming ingredients. These included a plant oil, such as sesame oil; phenolic acids, probably from an aromatic plant extract; and polysaccharide sugars from plants. Crucially, the recipe also contained dehydroabietic acid and other diterpenoids from conifer resin.

“The diterpenoids are antibacterial, which would have helped with preservation,” says analytical chemist Stephen Buckley from the University of York, who was part of the team. The researchers also found methyl esters of these diterpenoids, a chemical signature that the oil had been heated, probably during preparation of the balm. The recipe is broadly similar to that used for mummification throughout the 3,000-year history of ancient Egypt, Buckley says.

Maria Perla Colombini, an analytical chemist at the University of Pisa who works on cultural heritage but was not involved in this study, says the results are significant. “The identified balm materials are generally encountered in later embalming,” she says.

The mummy was originally buried in southern Egypt, possibly in the town of Gebelein, before it was brought to Turin about a century ago. In 2014, Buckley’s team found the same sort of embalming compounds in linen from pit graves in Mostagedda, more than 200 km northwest of Gebelein; the linens dated from 4500 to 3350 B.C. (PLOS One 2014, DOI: 10.1371/journal.pone.0103608). Buckley says this is evidence that a Pan-Egyptian identity, with shared cultural practices, existed before the pharaohs came along.

The nearest source of conifer resin would have been what is now Israel and the Palestinian territories, so the results also suggest that trade routes across the Middle East were well established by 3500 B.C. “It’s interesting because it would imply that there was regular trade going on, at a date much earlier than we had thought,” says Egyptologist Salima Ikram of the American University in Cairo, who was not involved in the work.

Investigating other prehistoric mummies could reveal even older examples of embalming, Buckley says. “My guess is that it’s likely to go back further.” But there are very few intact mummies from this period outside Egypt, and it is difficult to secure access for the tests.

Mummies still in Egypt are protected by stringent rules that restrict their transport and limit sampling of them. The GC/MS methods used in the study also require expensive equipment. Both factors have long stymied similar studies.

Ikram hopes this research could bolster the case for further investigations. “I think it’ll provide a push for getting a lot of the early materials tested.”