The first reliable source comes from the Atharvaveda in the Indian subcontinent. Written from 1200 – 900 A.D., it lists Cannabis as one of the five sacred plants.
In China, however, it is claimed that the “Green Emperor” Shenong was the first man to use it. He is also credited with inventing agriculture. Shenong seems to suggest that the Chinese had an extensive relationship with Cannabis; however, it is not known if he actually existed or if he is a myth. It is claimed that Shenong lived around 3,000 B.C.
It is likely that Cannabis had been used for centuries before it was mentioned. The fact that it was considered a sacred plant indicates that people were aware of the plant’s safety and understood its effects.