Historians have analysed the Vedas to posit a Vedic culture in the Punjab region and the upper Gangetic Plain. Most historians also consider this period to have encompassed several waves of Indo-Aryan migration into the Indian subcontinent from the north-west. The peepal tree and cow were sanctified by the time of the Atharva Veda. Many of the concepts of Indian philosophy espoused later, like dharma, trace their roots to Vedic antecedents.
Early Vedic society is described in the Rigveda, the oldest Vedic text, believed to have been compiled during 2nd millennium BCE, in the northwestern region of the Indian subcontinent. At this time, Aryan society consisted of largely tribal and pastoral groups, distinct from the Harappan urbanisation which had been abandoned. The early Indo-Aryan presence probably corresponds, in part, to the Ochre Coloured Pottery culture in archaeological contexts.
At the end of the Rigvedic period, the Aryan society began to expand from the northwestern region of the Indian subcontinent, into the western Ganges plain. It became increasingly agricultural and was socially organised around the hierarchy of the four varnas, or social classes. This social structure was characterised both by syncretising with the native cultures of northern India, but also eventually by the excluding of some indigenous peoples by labeling their occupations impure. During this period, many of the previous small tribal units and chiefdoms began to coalesce into Janapadas (monarchical, state-level polities).
In the 14th century BCE, the Battle of the Ten Kings, between the Puru Vedic Aryan tribal kingdoms of the Bharatas, allied with other tribes of the Northwest India, guided by the royal sage Vishvamitra, and the Trtsu-Bharata (Puru) king Sudas, who defeats other Vedic tribes—leading to the emergence of the Kuru Kingdom, first state level society during the Vedic period.