The Vedic sacrifices—yajñas or yāgas—are an ancient institution. According to the Bhagavadgītā (3.10 and 11) sacrifices were created by Prajāpati (Lord of men, the creator) himself at the very beginning of creation.
Among the various varieties of such sacrifices, the Sattrayāga is also one. It is the one sacrifice wherein all the priests who perform it are also the yajamānas (masters who reap the results equally). The duration of a Sattrayāga may be from 12 days up to a year or more. The Gavāmayana is a typical Sattrayāga, a model for such sacrifices of one year’s duration. It may be performed for various rewards like progeny, prosperity, greatness or heaven.
The sacrifice is performed in three phases. The first and the third are spread over 180 days (6 lunar months of 30 days) each. In between comes the viṣuvat or the central day.
Several rites like Abhiplava (a Soma ritual), Agniṣṭoma (a Soma sacrifice), Daśarātra (another rite of ten days’ duration) and Udayanīya (a concluding rite of any Somayāga) are involved in this Sattrayāga.
See also VEDIC SACRIFICES.