How and when did the religion Hinduism start?

Answer 1

First View:

Hinduism was discovered in India in the early Harappan period by the Vedas. They had migrated to India with the religion and it has since grown to be the worlds third largest religion.

Second View:

Hinduism was started or founded by an institution of Seven Sages called Saptarishis. Just as we have Pope for Christianity today, Hinduism, from the beginning, had an institution of seven sages who were the patriarchs of the Vedic religion. They very strictly guarded the Vedic body of knowledge, and the copy of the Vedas available to them was considered to be the final copy. They were considered as God's manifestation on earth, and their word was the final authority in religious matters.

Any changes to the Vedas were needed to be approved by this elite group of sages. If the reasons were justified, they approved the changes and incorporated them into the Vedas. Otherwise, they rejected it and kept the Vedas intact without any contamination. From what appears, they were extremely strict about changes to the Vedas. Even to this day of Hinduism, a word in Veda is normally considered as the final authority to the literal T. And this faith in Vedas was built upon a tradition where the Vedas were very strictly and jealously guarded from any changes whatsoever, unless the change really justified it. Some super human justification was required to have them changed. Any changes, to the extent possible, were always added as appendages rather than their being incorporated into the Vedas. So we have Brahmanas, Aranyakas, and Upanishads as appendages to the Vedas. As more and more philosophy developed, all of them got incorporated into this body as appendages.

It is this institution of seven sages that expended large amount of effort over thousands of years in unifying a large number of traditions from across continents and civilizations into one universal religion of Hinduism that we see today. The Hindu trinity, the Hindu divine hierarchy, the Hindu festivals, and everything else that we see today was formulated by them. It is they who declared Ram and Krishna to be the incarnations of Vishnu. It is they who inserted Purusha Sukta, Narayana Sukta, and Sri Sukta into the Vedas.

The names of the SaptaRishis carried over from one generation to the next. For example, if Kasyap dies, his son would take on the name of Kasyap and get inducted into the SaptaRishis. Once in a while, for some reason, like one of the seven rishis dying without having any children, the names of the one or more of the rishis changed, giving us a different set of SaptaRishis.

The religion got so excessively dependent on these sages that they started being considered as the representatives of the creator on earth. This slowly led to their deification and they started being mythicized. They were declared as the mind born sons of Brahma. Subsequently, they were equated with the most evolved light beings in the creation and the guardians of divine laws. Further deification of their attributes lead to the addition of more and more myths and halo around them. This sort of excessive mythicization finally lead to the relegation of this institution from the purview of the real world into the realm of mythology.

This institution got destroyed at the time of the three hundred year severe drought of 2200 BC. At that time, most of the Indians, devastated by the drought, left India for foreign shores, especially to European lands. Because of the severe suffering that people underwent because of the drought, people lost faith in a useless God who did not answer their prayers, leading to the rise of atheistic cults on the subcontinent. The institution of seven sages got destroyed in this religious upheaval, as a result of which, the origins of Hinduism have once and for all become lost in the dungeons of time.

(Excerpts from book "19000 Years of World History")