Humans began using cannabis as long as 10,000 years ago, researchers have found.
A new research, published in the journal of Vegetation History and Archeobotany, has linked the increased use of cannabis in East Asia with the rise of transcontinental trade between Europe and the East between 4,000 and 5,000 years ago, at the start of the Bronze Age.
One of the three key tribes that founded European civilisation – the Yamnaya people, based in what is now Eastern Europe – moved eastwards and are thought to have exported cannabis throughout Eurasia.
Pollen, fruit and fibres of cannabis have been turning up in Eurasian archaeological digs for several decades.
Despite assumptions by many that cannabis was first cultivated and used in China or Central Asia, the study points to an alternative theory.
It was at the start of the Bronze Age that cannabis use in East Asia intensified, and researchers say this is significant.
At that point the so-called Bronze Road to Asia, which later became known as the Silk Road, was being used to send goods east.
The researchers’ hypothesis is that one of the goods sent in that direction was cannabis.
Dr Tengwen Long, from the Free University of Berlin, said that the high value of cannabis would have made it ideal for trade, as a “cash crop before cash”.
He added: “The cannabis plant seems to have been distributed widely from as early as 10,000 years ago, or even earlier.”
David Anthony, who studies the Yamnaya, said: “The expansion of cannabis use as a drug does seem to be linked to movements out of the steppe.
“Cannabis might have been reserved for special feasts or rituals.”