The oldest layer of Indian religion is a world of hymns, not temples. Its gods are the powers of the natural and ritual order: Agni the fire that carries offerings to heaven, Indra the storm-king who drinks soma and hurls the thunderbolt, Varuna the guardian of cosmic law, Surya the sun, and radiant Ushas the dawn.

Worship is sacrifice: the fire altar, the poured offering, the precisely chanted verse. There are no avatars here, no temples, no image-worship. The gods are invoked, not visited, and the greatest of them is Indra, who will one day be reduced almost to a figure of fun.

The defining act of the Vedic world is Indra's slaying of Vritra, the serpent who coils around the mountains and holds back all the waters of the world. Strengthened by soma, Indra splits the dragon open with his thunderbolt, and the waters rush free like released cattle.

It is creation as combat, order wrested from obstruction, and for the Vedic poets it is the supreme divine act. But the very grandeur of the deed marks its moment: this is the high noon of Indra, and the sun is already beginning to set on the gods of the storm.

Over centuries the center of gravity shifts. Figures barely present in the Vedas rise to supremacy: Vishnu, a minor solar stride-taker, becomes the preserver of all worlds; Rudra the feared outsider becomes Shiva, the supreme ascetic; and Brahma takes the role of creator. The three great functions, creation, preservation, destruction, crystallize as the Trimurti.

Now come temples, images, and personal devotion. The remote gods of sacrifice give way to gods you can see, serve, and love, gods who descend into the world and take faces. The whole texture of worship changes.

Alongside the great gods rises the Great Goddess, and in the Shakta vision she is not a consort but the supreme power itself. The Devi Mahatmya declares her the force behind all the gods: Durga who slays the demon no god could kill, Kali who drinks the blood of Raktabija, and the gentle Parvati, Lakshmi, and Saraswati who are all her faces.

The theology is radical: the gods act, but she is the acting, the Shakti without which they are powerless. A tradition that began with an all-male pantheon of fire-priests now places a goddess at the very ground of being.