A 2,500-year-old stash of whole marijuana plants have been unearthed from an ancient tomb in northwest China. This discovery adds to a growing body of evidence that ancient people used marijuana for its psychoactive properties, and incorporated it into their rituals.

The plants were found lying like a burial shroud

A team of archaeologists, led by Hongen Jiang with the University of the Chinese Academy of Sciences, discovered 13 marijuana plants that were still largely intact, if yellowed and desiccated after millennia underground. In a first for funerary marijuana, the plants were found lying like a burial shroud atop the body of a man who had died in his mid-30s. Their roots lay below the man’s hips and the tips — which had been trimmed to remove the flowers — extended up around his face, according to the publication of the find in the journal Economic Botany.

This stash was found in one of 240 tombs that archaeologists had excavated in a desert region of the Turpan Basin in northwest China. The area had probably once been a stop along the Silk Road, and pastoral people called the Subeixi had lived and traded here, Kristin Romey for National Geographic reports. Three other tombs in this cemetery also contained marijuana fruits, leaves, stem fragments, and seeds. Scientists have wondered whether the marijuana plants came in via trade, or whether they had been farmed or grew wild in the region. Since the burial shroud marijuana plants were whole, uprooted plants, that suggests local growth.

Ancient people used marijuana for its psychoactive properties

Ancient people in Siberia and northwestern China have been putting pot in tombs since at least the first millennia BCE. An open question has been whether these plants were used for fruit, for their hemp fibers to make rope and clothing, or for what we use them for today: to get high, or to cut pain. So far, archaeologists have found 6,000 to 7,000-year-old hemp fabrics in Northern China, but haven’t unearthed any evidence of hemp clothing near the Turpan Basin before 2,000 years ago. While it’s possible that the clothes may simply have rotted over time, it’s also possible that the main purpose of marijuana wasn’t fiber.

In 2006, archaeologists found a large cache of marijuana fragments in a grave from around the same time period, at a nearby settlement. When scientists later analyzed the plants, they detected compounds that form when the main source of marijuana’s high — tetrahydrocannabinol, or THC — breaks down. That means these plants were probably prized for their psychoactive properties. This latest discovery of marijuana plants used as a burial shroud as well as the many previous findings of marijuana in the region’s tombs suggests that marijuana was used either medicinally or ritually, the authors write.