A large ancient stone jar at a burial site in Laos held the skeletal remains of at least 37 people, ranging from infants to adults, and was likely used as a collective tomb for generations, a new study has found.
Researchers say the discovery sheds significant light on one of Southeast Asia’s longest-standing archaeological mysteries. The study, led by Nicholas Skopal of James Cook University in Australia, was published in the journal Antiquity.
The jar sits at Site 75 on the Xieng Khouang Plateau in northern Laos, roughly 70 kilometers (43 miles) northeast of Phonsavan.
The site is the most northeastern jar site excavated to date on the Plain of Jars, a landscape containing hundreds of large hollowed stone containers spread across more than 120 known locations.
French archaeologist Madeleine Colani first surveyed the region in the 1930s, but the jars’ purpose has remained contested ever since.
Ancient burial jar at Laos site unlocks centuries of mystery
Skopal and his team excavated the jar across three field seasons from 2022 to 2024. The bones inside were largely disarticulated and densely packed, with skulls and long bones clustered near the jar’s edges.
This pattern points to secondary burial, a process where bodies decompose elsewhere first, and bones are later transferred to a final resting place. Radiocarbon dating of teeth and bone placed the burials between roughly 890 and 1160 AD, suggesting the jar served mortuary purposes for up to 270 years.
Researchers also found that some remains may have been selectively removed over time, since the bone count from skeletal elements was lower than what the dental remains suggested.
This raises the possibility that bones were later relocated to other sites, homes or places of worship, a practice documented across Iron Age and historical-period cultures in Thailand, Vietnam, Myanmar, and northeast India.
Bones tell the story of a 270-year collective burial cycle
Inside the jar, the team recovered an iron knife, a small copper bell, earthenware pottery, and 20 glass beads.
Chemical analysis of the beads traced their origins to South Asia, Mesopotamia, and possibly southeastern China or northern Vietnam. This points to the community’s participation in far-reaching trade networks connecting the Lao highlands to the Middle East and South Asia.
The team also found evidence of deliberate tooth removal, a practice observed in prehistoric populations across mainland Southeast Asia.
Additionally, trench excavations near the jar revealed that the surrounding landscape had been purposefully leveled and prepared before the jar was placed there, with jar-carving debris used as fill material.
Beads trace site 75 community to Mesopotamia and South Asia
Researchers also proposed that the seven smaller jars found 500 meters (1,640 feet) away at the same site may have served as primary containers where bodies initially decomposed, before bones were transferred into the larger jar.
This, they suggested, could explain why most stone jars across the Plain of Jars contain no human remains at all.
Skopal said the period of activity at Site 75 coincided with a time of intense regional connectivity. This overlapped with the commercial expansion of China’s Song Dynasty and the rise of the Khmer Empire.
Growing trade across Southeast Asia during this period likely facilitated the circulation of goods and cultural practices, reaching even remote highland communities in Laos.
