Hinduism is a complex phenomenon. It could be said that there are more religions within Hinduism than outside of it. Hinduism has never discarded or excluded anything, giving each teaching its particular niche within an ever-expanding framework of ideas, beliefs, and practices. In this way, Hinduism has been able to assimilate alien ideas and practices without forgoing its own fundamental teachings. The more it has changed, the more it has remained the same.
One way in which change has occurred within India’s religious culture is in the gradual eclipse of particular Deities and the emergence into prominence of other Gods and Goddesses. Thus, the great Vedic Deities Indra, Agni, Soma and Surya were superseded by the great Hindu Deities Shiva, Vishnu, Devi and Ganesha. It has been suggested that this change was the result of a resurgence of pre-Vedic non-Aryan traditions. But this is not borne out by the archaeological record. Otherwise, one would expect these later deities to somehow be associated with the Saraswati region and its mythology, which is not the case. Rather, Gods like Shiva and Vishnu could be said to reflect the heritage of the Ganga-Yamuna era of Puranic times, while the classic Vedic deities reflect the Indus-Saraswati phase.
The rise to prominence of such Deities has traditionally been understood as a development within the Vedic tradition itself, and not as the assimilation of non-Aryan Deities. Given the long history of India’s civilization, these changes can be expected. No outside influence need be invoked to account for the appearance of these popular Hindu Deities and the religious practices associated with them. They are crystallizations of theological-mystical imagery present already in the Rig-Veda (which incidentally has five hymns dedicated to Vishnu).
Whatever foreign elements were absorbed by the culture of early India, they did not change the core features of the Vedic heritage. This recognition brings immediate order and simplicity to the mass of historical facts. In addition, we do not need to interpret the Vedic tradition as being substantially at variance from later Hinduism, the two being separated by a strange and inexplicable rupture. Rather, we can look upon India’s spiritual heritage as a consistent cultural system, which happens to be the oldest surviving civilization in the world.
– Dr David Frawley (Courtesy : Excerpts from an article on cisindus.org, 30.1.2021) (Dr Frawley is a western born Hindu teacher in the Vedic tradition.)