Until relatively recently, the dominant theory was that the Aryans came into India from outside, perhaps as part of the same movements of people that led to the Hittites occupying parts of Anatolia, the Achaeans entering Greece, and the Kassites conquering Sumer — all in the period from about 1900 B.C.E. to 1750 B.C.E. Some scholars, however, have proposed that the Indo-European languages spread to this area much earlier; to them it seems possible that the Harappan people were speakers of an early Indo-European language. If that was the case, the Aryans would be one of the groups descended from this early population.

The central source of information on the early Aryans is the Rig Veda, the earliest of the Vedas, originally an oral collection of hymns, ritual texts, and philosophical treatises composed in Sanskrit between 1500 B.C.E. and 500 B.C.E. The Rig Veda portrays the Aryans as warrior tribes who glorified military skill and heroism; loved to drink, hunt, race, and dance; and counted their wealth in cattle. The Aryans did not sweep across India in a quick campaign, nor were they a disciplined army led by one conqueror. Rather they were a collection of tribes that frequently fought with each other and only over the course of several centuries came to dominate north India.

The key to the Aryans’ success probably lay in their superior military technology, including two-wheeled chariots, horses, and bronze swords and spears. Their epics present the struggle for north India in religious terms, describing their chiefs as godlike heroes and their opponents as irreligious savages who did not perform the proper sacrifices. In time, however, the Aryans clearly absorbed much from those they conquered, such as agricultural techniques and foods.

At the head of each Aryan tribe was a chief, or raja (RAH-juh), who led his followers in battle and ruled them in peacetime. The warriors in the tribe elected the chief for his military skills. Next in importance to the chief was the priest. In time, priests evolved into a distinct class possessing precise knowledge of the complex rituals and of the invocations and formulas that accompanied them. Below them in the pecking order was a warrior nobility who rode into battle in chariots and perhaps on horseback. The warrior class met at assemblies to reach decisions and advise the raja. The common tribesmen tended herds and worked the land. To the conquered non-Aryans fell the drudgery of menial tasks. It is difficult to define precisely their social status. Though probably not slaves, they were certainly subordinate to the Aryans and worked for them in return for protection.

Over the course of several centuries, the Aryans pushed farther east into the valley of the Ganges River, at that time a land of thick jungle populated by aboriginal forest peoples. The tremendous challenge of clearing the jungle was made somewhat easier by the introduction of iron around 1000 B.C.E., probably by diffusion from Mesopotamia.

As Aryan rulers came to dominate large settled populations, the style of political organization changed from tribal chieftainship to territorial kingship. In other words, the ruler now controlled an area with people living in permanent settlements, not a nomadic tribe that moved as a group. Moreover, kings no longer needed to be elected by the tribe; it was enough to be invested by priests and to perform the royal ceremonies they designed. The priests, or Brahmins, supported the growth of royal power in return for confirmation of their own power and status. The Brahmins also served as advisers to the kings. In the face of this royal-priestly alliance, the old tribal assemblies of warriors withered away. By the time Persian armies reached the Indus around 513 B.C.E., there were sixteen major Aryan kingdoms in north India.