The Vedic Period (c. 1500 - c. 500 BCE) is the era in which the Vedas were committed to writing, but this has nothing to do with the age of the concepts or the oral traditions themselves.
The designation “Vedic Period” is a modern construct, which relies on evidence of an Indo-Aryan migration, which, as noted, is not universally accepted. Even so, that is the theory most commonly accepted as historically accurate based on the available evidence. The development of the texts is described by scholar John M. Koller:
"The Vedic age began when the Sanskrit-speaking peoples began to dominate life and thought in the Indus Valley, probably between 2000 and 1500 BCE. Historians used to think that these Sanskrit-speaking peoples who called themselves Aryans came to the Indus valley in northwest India as conquerors some thirty-five hundred years ago. But recent scholarship has challenged this thesis of conquering Aryans. What we do know is that the earlier Indus culture, which flourished from 2500 to 1500 BCE, and which, judged by its archaeological remains, was quite sophisticated, declined at this time. We also know that the Vedic thought and culture reflected in the Rig Veda has a continuous history of dominance in India during the last thirty-five hundred years. It is likely that the cultural traditions of the Vedic peoples mingled with the traditions and customs of the Indus people."
The religious beliefs of the people of the Harappan Civilization are unknown as they left no written works. Excavations at Mohenjo-Daro, Harappa, and other sites suggest a highly developed belief structure which involved ritual bathing and some form of worship service. The only clear evidence of religious belief and practice comes from statuary of the nature spirits known as yakshas which date to before c. 3000 BCE in rudimentary form and continue, with greater refinement, through the 1st century BCE.
The Yaksha Cults seem to have focused on daily need (if one interprets the evidence along the lines of ancestor cults) as the spirits could be benevolent or malevolent, and sacrifices were made either for favors asked or to ward off harm. As in Asian ancestor cults, there was no emphasis on the “big picture” of where human being came from, what their purpose might be, or where they went after death. These were the questions addressed by the first of the Vedas, the Rig Veda (meaning either “Knowledge of Wisdom”, “Verses of Wisdom” or, literally, “Praise Knowledge”) which informs the other three.