Explore the vast library of ancient historical chronicles, theological legends, and complex models of cosmic time scales that form the heartbeat of popular Hinduism.

Figure 1: Lord Maha Vishnu resting on Sheshanaga in the cosmic ocean of milk (Kshira Sagara), initiating the endless cycles of creation (Sarga) and dissolution (Pralaya).
The Sanskrit word Purana literally translates to "ancient" or "that which is old yet new." Composed by Sage Vyasa, the Puranas were written to translate the highly abstract, non-dual philosophy of the Upanishads into **accessible, story-based narratives** for the general public.
Rather than relying on dry, logical formulas, the Puranas utilize rich, colorful metaphors, historical genealogies, and legendary dialogues between gods, sages, and kings. They cover an astonishing array of subjects—cosmology, astronomy, temple architecture, gemstone therapy, grammar, medicine, and the sacred duties of different stages of human life.
According to ancient lexicography (specifically the Amarakosha), a true, complete Purana must discuss five distinct thematic layers:
The 18 Great Puranas (Mahapuranas) are classified into three major groups of six books each, aligned with the dominant **Guna (cosmic quality)** and its presiding deity:
The Puranas detail a mind-boggling, cyclical concept of time, matching modern astrophysics. One complete cosmic cycle is a **Mahayuga** (4.32 million solar years), which is divided into four downward-stepping ages:
A total of 1,000 Mahayugas forms just one single day of Brahma, called a **Kalpa** (4.32 billion years), followed by an equal night of rest where the universe dissolves (Pralaya). A Brahma lives for 100 cosmic years (311.04 trillion years), which is exactly one exhale of Lord Maha Vishnu!