Early Vedic Period and Later Vedic period

Early Vedic Period (ca. 1500–1100 BCE)

These migrations may have been accompanied with violent clashes with the people who already inhabited this region. The Rig Veda contains accounts of conflicts between the Aryas and the Dasas and Dasyus. The Rig Veda describes Dasas and Dasyus as people who do not perform sacrifices (akratu) or obey the commandments of gods (avrata). Their speech is described as mridhra which could variously mean soft, uncouth, hostile, scornful or abusive. Other adjectives which describe their physical appearance are subject to many interpretations. However, many modern scholars connect the Dasas and Dasyus to Iranian tribes Dahae and Dahyu and believe that Dasas and Dasyus were early Indo–Aryan immigrants who arrived into the subcontinent before the Vedic Aryans.

Internecine military conflicts between the various tribes of Vedic Aryans are also described in the Rig Veda. Most notable of such conflicts was the Battle of Ten Kings, which took place on the banks of the river Parushni (modern day Ravi). The battle was fought between the tribe Bharatas, led by their chief Sudas, against a confederation of ten tribes— Puru, Yadu, Turvasha, Anu, Druhyu, Alina, Bhalanas, Paktha, Siva, Vishanin. Bharatas lived around the upper regions of the river Saraswati, while Purus, their western neighbours, lived along the lower regions of Saraswati. The other tribes dwelt north-west of the Bharatas in the region of Punjab.Division of the waters of Ravi could have been a reason for the war. The confederation of tribes tried to inundate the Bharatas by opening the embankments of Ravi, yet Sudas emerged victorious in the Battle of Ten Kings.[40] Purukutsa, the chief of Purus, was killed in the battle and the Bharatas and the Purus merged into a new tribe Kuru after the war.

Later Vedic period (1100–500 BCE)

Modern replica of utensils and falcon shaped altar used for Agnicayana, an elaborate srauta ritual originating from the Kuru Kingdom,around 1000 BCE.

After the 12th century BCE, as the Rig Veda had taken its final form, the Vedic society transitioned from semi-nomadic life to settled agriculture. Vedic culture extended into the western Ganges Plain.The Gangetic plains had remained out of bounds to the Vedic tribes because of thick forest cover. After 1000 BCE, the use of iron axes and ploughs became widespread and the jungles could be cleared with ease. This enabled the Vedic Aryans to settle at the western Gangetic plains.Many of the old tribes coalesced to form larger political units.

The Vedic religion was further developed when the Indo-Aryans migrated into the Ganges Plain after c. 1100 BCE and became settled farmers, further syncretising with the native cultures of northern India. In this period the varna system emerged, state Kulke and Rothermund, which in this stage of Indian history were "hierarchical order of estates which reflected a division of labor among various social classes". The Vedic period estates were three, Brahmin priests and warrior nobility were first, peasants and traders as second, and laborers and artisans belonging to indigenous (non-Aryan) people were third.This was a period where agriculture, metal and commodity production as well trade greatly expanded, and the Vedic era texts including the early Upanishads and many Sutras important to later Hindu culture were completed.

The Kuru Kingdom, the earliest Vedic "state", was formed by a "super-tribe" which joined several tribes in a new unit. To govern this state, Vedic hymns were collected and transcribed, and new rituals were developed, which formed the now orthodox Srauta rituals.Two key figures in this process of the development of the Kuru state were the king Parikshit and his successor Janamejaya, transforming this realm into the dominant political and cultural power of northern Iron Age India.

The most famous of new religious sacrifices that arose in this period were the Ashvamedha (horse sacrifice). This sacrifice involved setting a consecrated horse free to roam the kingdoms for a year. The horse was followed by a chosen band of warriors. The kingdoms and chiefdoms in which the horse wandered had to pay homage or prepare to battle the king to whom the horse belonged. This sacrifice put considerable pressure on inter-state relations in this era. This period saw also the beginning of the social stratification by the use of Varna, the division of Vedic society in Kshatriya, Brahmins, Vaishya and Shudra.

The Kuru kingdom declined after its defeat by the non-Vedic Salva tribe, and the political centre of Vedic culture shifted east, into the Panchala kingdom on the Ganges. Later, the kingdom of Videha emerged as a political centre farther to the East, in what is today southern Nepal and northern Bihar state in India, reaching its prominence under the king Janaka, whose court provided patronage for Brahmin sages and philosophers such as Yajnavalkya and Uddalaka Aruni.

Second urbanisation

By the 6th century BCE, the political units consolidated into large kingdoms called Mahajanapadas. The process of urbanisation had begun in these kingdoms and commerce and travel, even over regions separated by large distances became easy. Anga, door step of modern-day West Bengal, a small kingdom to the east of Magadha, formed the eastern boundary of the Vedic culture. Yadavas expanded towards the south and settled in Mathura. To the south of their kingdom was Vatsa which was governed from its capital Kausambi. The Narmada River and parts of North Western Deccan formed the southern limits. The newly formed states struggled for supremacy and started displaying imperial ambitions.

The end of Vedic India is marked by linguistic, cultural and political changes. The grammar of Pāṇini marks a final apex in the codification of Sutra texts, and at the same time the beginning of Classical Sanskrit. The invasion of Darius I of the Indus valley in the early 6th century BCE marks the beginning of outside influence, continued in the kingdoms of the Indo-Greeks.[58] Meanwhile, within India, the shramana movements (including Jainism and Buddhism) challenged the authority and orthodoxy of Vedic scriptures and ritual.