This question arises because we take for granted that a religious tradition must necessarily be founded, and that it must be historical; but this is not the case with Hinduism. It was not founded by an individual and we do not think that it even has a beginning.
The fundamental scriptures of Hinduism are the Vedas. The word Veda is derived from the root ‘vid’, which means “to know.” The Vedas are a body of sacred knowledge or wisdom, Knowledge is never created. It is eternal. It just becomes manifest. The Vedas consist of mantras, the sacred hymns and passages. They were not composed, but were revealed to the risis, or the sages, who on account of the power they attained due to penance, concentration, and devotion and worship of the Lord, attained a very refined state of mind, in which they were able to see the mantras. Thus Vedas are not written by anybody. The eternal knowledge that they teach was revealed to the sages by Isvara, God.
Like the laws of nature, that scientists such as Newton and Einstein came to understand later, always existed, the Vedas were always there, and since they are a collection of the revelations that many sages received, it is the truth revealed in them, and not one who speaks in them, is important.
Humans have a natural urge to know and to live the truth. Our intellect has a natural affinity for the truth. It never wants falsehood. This is expressed in the famous prayer in the Brhadaranyaka Upanisad, “Lord, please lead me from untruth to truth, from darkness to light, from death to immortality.” (1—3-28) The Vedas reveal a way of life to fulfill this human urge.
However great a person is, his statements and insights are limited by the limitations of the human intellect, such as ignorance, doubt, misapprehension etc., and by the limitations of the senses and the mind. As a consequence, books written by them will reflect those limitations. Since the Vedas were revealed, and not composed, they are free from the limitations, or defects, of the human intellect. We therefore look upon them as pramana, or a valid means of knowledge.
In summary, Hinduism has no beginning, was not founded by a single person, and is hence not limited to the views and teachings of a person. Its teachings are based on the Vedas, and are broad and universal. Since the Vedas reveal the fundamental truth of life, and the truth has no beginning, it can be said that the Hindu religion also has no beginning. It is as ancient as mankind.
Swami Viditatmanand Sarswati