Archaeologists working near Bolivia’s Lake Titicaca have unearthed evidence of an ancient mortuary complex that ritually processed human remains by boiling, defleshing and cleaning corpses and converting them into more portable bones that could be carried away by the nomadic people who once lived in the Andes Mountains.

Nearly 2,000 years ago, trade caravans and llama drovers crisscrossed the foothills of the Andes Mountains near the southern shores of Lake Titicaca in present-day Bolivia. Among the sporadic outposts frequented by the nomads was the religious and political center of Khonkho Wankane, and a new study published in the current issue of the journal Antiquity reveals that the itinerant populations who frequented the settlement between 200 B.C. and A.D. 500 once brought their dead in tow so that the corpses could be ritually processed into more portable pieces for burial elsewhere.

The article, written by Franklin & Marshall College archaeology professor Scott C. Smith and colleague Maribel Pérez Arias of the University of Pittsburgh, details their unexpected find at Khonkho Wankane. The archaeologists unearthed the remnants of a circular, stone-and-adobe structure in the center of the settlement along with 972 human bones from at least 25 individuals strewn across the floor. Outside of the intact bones of one hand and one foot, the majority of the human remains they discovered were scattered teeth and small bones, mostly from the hands and feet. Examinations determined that the majority of the bones came from adults older than 25 years of age. A thin layer of white plaster covered the remains, and most showed evidence of having been painted with red pigment. The archaeologists found ceramic pots and four tools sculpted from llama bones that were also coated by the same white plaster.

X-ray fluorescence tests performed on 27 blocks of a white, chalky material found at the site revealed that they were principally composed of calcium oxide—quicklime—produced by heating limestone at extremely high temperatures. When exposed to air, quicklime is converted into a white calcium carbonate plaster similar to that found coated on the bones at Khonkho Wankane.

Based on the presence of the quicklime and the absence of any long bones and intact skulls at the site, the archaeologists surmised that the circular structure they unearthed had been a mortuary complex that processed human remains. Similar to how leather producers remove hair and fats from hides in a process called “liming,” the mortuary workers at Khonkho Wankane disarticulated corpses brought to them by nomads and then boiled the pieces in large cooking pots filled with water mixed with quicklime, a caustic brew that would strip muscle tissue and fat from the bones before they were cleaned. Workers used the llama-bone tools to stir and manipulate the contents of the cooking vessels. The presence of the red pigment suggests that the ritual process included painting the bones after they were cleaned.

Four carved sandstone monoliths found at Khonkho Wankane offer further clues to the original use of the circular structure. The carvings on one stone pillar depict an individual appearing to move up the back of the monolith covered in flesh and then down with its ribs exposed and body partially defleshed.

Isotope analyses of the bones and teeth uncovered at Khonkho Wankane found they have signatures outside the range for the area near the southern shores of Lake Titicaca. According to the article, the finding indicates “that the individuals processed in this structure did not live near this region during dental enamel formation,” and it suggests that corpses were specifically brought to the settlement for processing.

Why would the ancient civilization that once lived high in the Andes build such a mortuary? One reason is that the dead were revered by the living and played an important role in the civilization. Secondly, in a highly mobile society, family members often passed away far from home, and rather than burying their ancestors where they died, relatives carried their bodies with them to more suitable burial grounds. Thus, the mortuary served as a way station that would convert heavy corpses into a more easy-to-carry collection of bones, ribs and skulls that could be taken for burial closer to home.

“The evidence suggests,” Smith and Pérez write, “that during a time of heightened movement and circulation, Khonkho Wankane was propelled to prominence in part because of a ritual process of preparing human remains for a mobile agropastoral population.”