The Vedic Age [1500 BC - 1000 BC]
The Aryans migrated from the North-west to the area called Sapta-Sindhava (the land of the seven rivers) – Eastern Afghanistan, Punjab and the fringes of western Uttar Pradesh. All that is known of the half millennium following the fall of the Indus Civilization comes from the Vedas, a collection of sacred hymns attributed to the Aryans. They prepared the first and oldest collection of mystical hymns, known as the Rig Veda, which is the only source of information on early Vedic life. The other three Vedas, Sama, Yajur, and Atharva were written much later.
Early Aryans were semi-nomadic and kept large herds of cattle. As they settled down in villages, they also became cultivators, using ox to draw their ploughs. They were ruled by warriors, who depended upon priests to perform the rituals to protect their crops and cattle, and insured victory in war. The strength of the Aryan tribes was determined by its Jana (people) and not Janapada (land). The Indian sub-continent got it’s name Bharat Varsha after the tribe Bharata, which was the strongest one.
The early Vedic religion was a form of nature worship. Evidently, there were neither temples nor idols. The mode of prayer was recitation of mantras. Sacrifice was offered for Praja (children), Pasu (cattle) and Dhana (wealth) and not for spiritual upliftment or misery. When the Aryans first came to India, there was no consciousness of caste, nor were the professions hereditary. The word ‘Varna’ is used in the Rig Veda with reference to only the Aryan or Dasa having respectively, fair or dark complexion, but never with reference to the Brahmana or Rajanya (Kshatriya).
During the later Vedic phase, the Aryans moved away from their early settlements to the Ganga-Jamuna- Doab. The Ramayana has partly unfolded the tale of the Aryan advent into the south.
Source : http://www.indiainfocentre.com/history/the-vedic-age-1500-bc-1000-bc