Buddhism does not seem to have spread beyond the areas where the Buddha lived and taught until a formal programme of dissemination was planned in the 3rd century BC by Mogaliputta Tissa, a celebrated Buddhist elder. Convening what is known as the Third Council, Mogaliputta Tissa organised the official writing down of Buddhist scriptures and a concerted campaign of missionary activity.

The monks sent to the Himalayan region founded an early school known as the Hemavatas. The Hemavatas are the only group organised by Mogaliputta Tissa for which archaeological evidence has been found. A group of inscribed reliquaries dating to the 2nd century BC provide the names of five monks, all of whom are mentioned in Buddhist historical sources. The reliquaries prove that the Buddhist historical tradition is based on actual events and that there was a clear memory of the Third Council in the 2nd century BC – 100 years after the Council met.

Although the Hemavata reliquaries and inscriptions were found at Sānchī in central India and neighbouring sites, the Hemavatas did not originate in that area but were brought there from north India as part of a major programme of revitalisation and expansion in the 2nd century BC.