During this era (500 BCE to 500 CE) Hinduism became more like it is today, with the worship of Shiva, Vishnu, and the Goddess, as opposed to primarily the older Vedic gods (Indra and others).
Various scriptures honoring these newer gods were put down into writing in the early centuries CE. Many of them are known as Puranas, each one explaining the origins and powers of Shiva, Vishnu, Devi, etc.
These new scriptures coincided with a general spread of Sanskritic religious literature throughout India at this time, which further consolidated Hindu devotional traditions.