In the historical Vedic religion

Historical Vedic religion

The religion of the Vedic period is a historical predecessor of Hinduism. Its liturgy is reflected in the mantra portion of the four Vedas, which are compiled in Sanskrit. The religious practices centered on a clergy administering rites...

, Pravargya was a ceremony introductory to the Agnishtoma (Soma sacrifice), at which fresh milk is poured into a heated vessel called mahavira or gharma and offered to the Ashvins

Ashvins

The Ashvins , in Hindu mythology, are divine twin horsemen in the Rigveda, sons of Saranya , a goddess of the clouds and wife of Surya in his form as Vivasvat. The Ashvins are Vedic gods symbolising the shining of sunrise and sunset, appearing in the sky before the dawn in a golden chariot,...

. The ceremony is described in details in the technical texts on proper ritual, the Brahmanas, Aranyaka

Aranyaka

The Aranyakas are part of the Hindu śruti, the four Vedas; they were composed in late Vedic Sanskrit typical of the Brahmanas and early Upanishads; indeed, they frequently form part of either the Brahmanas or the Upanishads....

s and Shrautasutras.

The ritual

The whole Pravargya ritual has two distinct parts: the preparation of the earthen implements, especially the gharma or mahavira and the rites performed on the latter immediately after taking out of the furnace. These rites include the offering of hot milk to the Ashvins, and repeating it in the evening and so for three consecutive days preceding the upasad. At its conclusion, the implements used in this ritual, particularly the mahavira are carried in procession to uttaravedi and buried there.