According to legend, the last Aztec emperor, Montezuma II, relied on a daily dose of chocolate—he reportedly drank gallons of it every day—to revitalize himself.
It’s long been thought that Montezuma’s people first learned of chocolate, then enjoyed mainly as a bitter drink, from their Mayan neighbors, who in turn drew on knowledge passed down by the Olmecs. But a study recently published in Nature Ecology and Evolution suggests the classic treat actually originated in another part of the world: the Amazon rainforest. And that’s not all—as Colin Barras reports for Science magazine, the new findings place the birth of chocolate some 5,300 years ago, or nearly 1,500 years earlier than previously believed.
Michael Blake, an archaeologist at Canada’s University of British Columbia, decided to take a closer look at the history of chocolate after spotting some elaborate drinking vessels at an Ecuadorian dig site called Santa Ana-La Florida. (The ancient village, which hosted members of the Mayo-Chinchipe civilization around 5,500 years ago, has yielded a wealth of insights since its rediscovery in 2002.) Blake noticed that the vessels found at Santa Ana-La Florida bore marked similarities to those used by the Maya to make cacao beverages.
“I asked: ‘Is there any chance that these vessels might also have been used for cacao?’” he explains in an interview with Barras. “And the answer came back: ‘Well, nobody’s looked.’”
To test the theory, Blake and his colleagues pursued three separate lines of investigation. First, Bruce Bower writes for Science News, the team examined charred cooking residue left on the surface of certain stone artifacts and ceramic shards. These lingering remnants of ancient meals contained starch grains unique to Theobroma cacao (the cacao tree), providing evidence that was further backed up by the discovery of theobromine, a chemical compound seen in seeds of the domesticated cacao plant, in 25 ceramic and 21 stone artifacts. Finally, Ars Technica’s Jennifer Ouellette notes, the researchers conducted genetic analysis of DNA fragments left on the artifacts and realized they contained sequences specific to domesticated variants of T. cacao.
In a statement, lead author Sonia Zarrillo of the University of Calgary explained that this trifecta of evidence enabled the team to “definitively identify a plant that is otherwise notoriously difficult to trace in the archaeological record because seeds and other parts quickly degrade in moist and warm tropical environments."
The results aren’t completely out of left field, Rosemary Joyce, an archaeologist at the University of California, Berkeley who was not involved in the study, tells Science’s Barras. Previous studies have shown the cacao tree reaches peak genetic diversity in the upper Amazon rainforest, suggesting this region actually served as the original cradle of chocolate.
Still, prior to the new study—which represents not only the earliest archaeological evidence of cacao use, but the only evidence found in South America thus far—scholars had traced the origins of chocolate to the ancient civilizations of Central America, which offer both textual and physical documentation of cacao use dating back to around 1900 B.C.
Mesoamericans such as the Aztecs and Mayans prized cacao for both its culinary properties and surprising cultural significance, George Dvorsky explains for Gizmodo. Some groups used cacao beans as currency; others elevated chocolate to the level of the gods, placing bitter cocoa drinks at the center of ritual celebrations and feasts.
But as the team’s findings reveal, the civilizations long touted as the world’s first chocoholics owe much to their South American neighbors.
“People in the upper reaches of the Amazon basin, extending up into the foothills of the Andes in southeastern Ecuador, were harvesting and consuming cacao that appears to be a close relative of the type of cacao later used in Mexico,” Blake concludes in a statement. “… This suggests that the use of cacao, probably as a drink, was something that caught on and very likely spread northwards by farmers growing cacao in what is now Colombia and eventually Panama and other parts of Central America and southern Mexico."