Central Eurasia’s Yamnaya people – thought to be one of the three key tribes that founded European civilisation – dispersed eastwards at this time and are thought to have spread cannabis, and possibly its psychoactive use, throughout Eurasia.
The pollen, fruit and fibres of cannabis have been turning up in Eurasian archaeological digs for decades. It is often assumed that cannabis was first used, and possibly domesticated, somewhere in China or Central Asia, the researchers say – but their database points to an alternative.
Some of the most recent studies included in the database suggest that the herb entered the archaeological record of Japan and Eastern Europe at almost exactly the same time, between about 11,500 and 10,200 years ago.
“The cannabis plant seems to have been distributed widely from as early as 10,000 years ago, or even earlier,” says Long. The researchers suggest that different groups of people across the Eurasian landmass independently began using the plant at this time – perhaps for its psychoactive properties or as a source of food or medicine, or even to make textiles from its fibres.
This earlier “Bronze Road” allowed all sorts of commodities to spread between west and east, potentially including cannabis.
“It’s a hypothesis that requires more evidence to test,” says Long, but he points out that the high value of cannabis would have made it an ideal exchangeable good at the time – a “cash crop before cash”.
And independent lines of evidence suggest that commodities and people were on the move in the early Bronze Age. For instance, Long says that wheat, which was cultivated about 10,000 years ago in the Near East, first appeared in China 5000 years ago.
Ancient DNA studies published in the last few years also confirm that one nomadic pastoral population of the steppe – the Yamnaya – began spreading both east and west at this time too.
There are reasons to believe that its mind-bending properties were a factor. Some researchers have suggested that burned cannabis seeds found at archaeological sites hint that the Yamnaya carried the idea of smoking cannabis with them as they spread across Eurasia.