The Seekers of Truth.

While Brahmin priests continued to practice and preserve Aryan rituals, and to absorb local ( Harappan?) deities into Hindu religious practice, there were others (many of them Brahmins themselves) who undertook their own quests for Truth.

The Vedas evolved into the Upanishads, which can be conceived as commentaries on the Vedas.For a summary, follow this link.

Vedanta( which translates into "The end of the Vedas" or perhaps "The summary of the Vedas" was a further evolution.It appears to be a conscious effort to avoid the obsession with rituals that pervade the earliest Vedas and grapple with central and profound philosophical questions.
For a bird's eye view, follow this link.In the Vedanta, the polytheism of the Rig Veda tradition transforms itself into not only monotheism (the concept of Ishwara) but a unification of Creation and Creator (the concept of Brahman).

The philosophers of Vedanta were perhaps stimulated by others who set up distinctly separate religions- Mahavira and Siddharta.

Mahavira(599-527 BC) and Siddharta( 5560-480 BC) were born into royal households that were situated near each other viz. Kundapura in Bihar and Kapilavastu in Nepal.There is evidence to show that they were even closer in age than official dates suggest.Both renounced the world as young men, and turned their attention to the problem of determining the right conduct by which ordinary men and women cope with pain and suffering.Both men arrived at their respective visions of the Truth after long years spent in meditation and asceticism.Neither was overly concerned with the existence or non-existence of God.Both went on to lay the foundations of mainstream religions.

Mahavira was the twenty-fourth ( and last) 'Tirthankara' (or Great Spiritual Leader) of the Jain Tradition ,which co-existed with the Vedanta Tradition.(For a description, follow this link.Apart from contributing significantly to this tradition, he preached to and converted his followers, and organized them into monks and laymen. Jainism has about five million followers world-wide today, mostly in India.

Siddhartha took the name of Gautam on attaining enlightenment, and founded Buddhism.He was called "The Buddha" by his followers in reverence.His teachings often run parallel to those of Mahavira, though there are significant differences.For one thing, his avoidance of extreme forms of asceticism for the common man or woman may have made his teachings more palatable to would-be converts than Jainism.His followers spread Buddhism far and wide, not only in the Indian Sub-Continent but also to Sri Lanka,Afghanistan,Tibet,South-East Asia, Central Asia and the Far East.There is an estimated number of sixty million Buddhists in the world today.

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