One of the early confederations of the Tarai is the Shakya clan, whose seat apparently is Kapilvastu, near Nepal's present-day border with India.

The clan's most renowned son is Siddhartha Gautama (ca. 563-483 BCE), a prince who rejects the world to search for the meaning of existence and becomes known as the Buddha, or the Enlightened One.

The earliest stories of his life recount his wanderings in the area stretching from the Tarai to Banaras on the Ganges River and into modern Bihar State in India, where he finds enlightenment at Gaya—still the site of one of the greatest Buddhist shrines.

After his death and cremation, his ashes are distributed among some of the major kingdoms and confederations and are enshrined under mounds of earth or stone called stupas.

Certainly, his religion is known at a very early date in Nepal through the Buddha's ministry and the activities of his disciples.