A type of beer containing the psychoactive seeds of a South American tree may have helped an empire maintain political order. According to a new study in the journal Antiquity, the Wari Empire – a pre-Columbian empire in what is now Peru that existed from around 600 to 1000 CE – may have been the first in the region to allow for mass consumption of psychedelic drugs, enabling the entire population to share in mind-altering experiences during large communal feasts.

The ancient civilizations of the Andean highlands made use of several hallucinogenic plants, including the mescaline-containing San Pedro cactus and the seeds of the Anadenanthera colubrina tree, known colloquially as vilca. The latter contains an analog of the highly potent psychedelic compound DMT,  ingested as snuff by South American shamans for at least 4,000 years.

As DMT is broken down by monoamine oxidase (MAO) in the stomach, however, orally ingested vilca produces no psychoactive effects unless it is consumed in conjunction with an MAO inhibitor, hence its traditional insufflation. Yet, while excavating the Wari outpost of Quilcapampa, archaeologists discovered evidence of vilca seeds that appear to have been mixed with a kind of beer known as chicha. They say this may have potentiated the psychedelic effects of these seeds.

According to the researchers, chicha probably acted as a “moderate MAO inhibitor.” The addition of vilca to this brew would therefore have created a type of psychedelic punch that could be distributed to attendees at large gatherings. By sharing the drug in this way, the Wari elite appear to have broken with tradition by allowing the entire community to partake in a substance that was previously accessible only to high priests and rulers.

In their write-up, the authors explain that the traditional snorting of vilca “induced sharp, powerful psychotropic effects that were more conducive to an individualising experience,” but that “the oral consumption of vilca in [chicha] changed the experience, most likely creating weaker but more enduring effects that could be enjoyed collectively.”

By sharing this experience with the masses, the Wari elite possibly hoped to inspire a deep bond between all members of the community, strengthening the group. At the same time, by hosting great feasts and providing access to this divine brew, the rulers maintained their position of superiority and created a sense of indebtedness among the general population, who otherwise would never be able to enjoy such as experience.

Within the context of ancient Andean geopolitics, this shift in drug use can be seen as a pivotal moment leading to a fundamental change in how empires were organized. According to the study authors, early Andean dynasties maintained their hierarchical structure by limiting the use of sacred hallucinogenic plants to elites, thus ensuring the authority of these privileged individuals by granting them exclusive access to spiritual realms.

Later civilizations such as the Incan Empire, however, are known to have relied on the communal consumption of maize beer in order to maintain social cohesion. The study authors suggest that the adoption of vilca-infused chicha by the Wari “represents a fulcrum of Andean political development, wherein larger numbers of participants could collectively experience the effects of a hallucinogen.”

“The resulting psychotropic experience reinforced the power of the Wari state, and represents an intermediate step between exclusionary and corporate political strategies,” they write.

In other words, by plying their subjects with drugs, it seems that “Wari leaders were able to legitimize and maintain their heightened status.”