The first pot trade happened 5,000 years ago, a new study revealed.

A review of cannabis archaeology revealed that the Yamnaya people, a group of nomads who entered Europe about 5,000 years ago from the eastern Steppe region (today's Ukraine and Russia), were responsible for the first transcontinental trade of cannabis.

The Yamnaya, who were also believed to have been among the founders of Western civilization, brought with them the skill and knowledge of metallurgy, herding and possibly Indo-European languages, the researchers said.

According to the researchers from the German Archaeological institute and the Free University of Berlin, the discovery is based on evidence of cannabis pollen, fruits and fibers that were found during archaeological digs across Europe and East Asia.

"Cannabis seems to have grown as a component of natural vegetation across Eurasia from the early Holocene," Tengwen Long and Mayke Wagner from the German Archaeological Institute, and Pavel Tarasov from the Free University of Berlin, wrote in a statement published in Live Science.

The herb was thought to be first used and domesticated in China or Central Asia. But the recent study revealed that cannabis was actually used in Europe and East Asia between 11,500 and 10,200 years ago.

According to the researchers, cannabis had been used in the region for its psychoactive properties or as a source of food or medicine. The plant fiber was also said to be used in making textiles.

But the cannabis use intensified during the Bronze Age, during the time nomadic pastoralists on the Steppe region, the Yamnaya, had started traveling about and began transcontinental trading.

The researchers also believed that cannabis had been used as a "cash crop" during this period.

"Cannabis's multiple usability might have made it an ideal candidate for being a 'cash crop before cash', a plant that is cultivated primarily for exchange purpose," Long said.

According to Dave Anthony of Hartwick College in Oneonta, New York, who studies the Yamnaya tribe and was not involved in the research, the Yamnaya people could have used cannabis for its psychoactive properties on certain special occasions.

"The expansion of cannabis use as a drug does seem to be linked to movements out of the steppe," he told SBS Australia.

"Cannabis might have been reserved for special feasts or rituals."

The researchers said that they would conduct further studies about prehistoric cannabis trade and collect more data from the Eurasian steppe region.