In the developed Vedic ritual system, the fully-established Brahmin householder maintains not one but three sacred fires — the tretāgni (त्रेताग्नि), the "three fires." Each has its own location, its own shape of altar, its own function, and its own daily and seasonal offerings. To maintain these fires unbroken for life is the highest ritual obligation of the Vedic householder, and one who undertakes it is called an āhitāgni — "one who has established the fires."
The Three Fires
1. Garhapatya
The Gārhapatya (गार्हपत्य) — from gṛha-pati, "householder" — is the household fire. Its altar is circular, located in the western part of the sacrificial enclosure. It is the parental fire from which the other two are kindled; without the gārhapatya the other two cannot exist.
The garhapatya is the fire of cooking (the priest's daily food is cooked on it), of the daily morning and evening offerings to Agni Vaiśvānara, and of all routine domestic rituals. Tradition holds that the fire is to be kept burning continuously from the householder's wedding ceremony — when it is first kindled in his presence — until his death, when his own body will be cremated using it. To let the garhapatya go out is a serious ritual lapse requiring prāyaścitta (atonement).
2.
The Āhavanīya (आहवनीय) — from ā-hu-, "to offer" — is the offering fire. Its altar is square, located in the eastern part of the enclosure. The square shape is read in the Brahmanas as representing the heavens; the eastern direction is the direction of the rising sun and of the gods.
The is the fire into which the havis (the consecrated offering substances — ghee, grain, plant matter, soma) is poured during the great public sacrifices. The mantras of the Yajurveda are recited as offerings are made into this fire. The priest faces east, the offering rises eastward in the smoke, and the gods are conceived to receive it directly from this altar.
3. Dakshinagni
The Dakṣiṇāgni (दक्षिणाग्नि) — from dakṣiṇa, "south" — is the southern fire. Its altar is semicircular, located in the south of the enclosure. The south is the direction of the ancestors (pitṛs) in Vedic cosmology, and the dakshinagni is the fire associated with ancestral rites — the śrāddha offerings made for the departed.
The dakshinagni also has a defensive function: it is described as the fire that protects the sacrificer from the influences that come from the south, the direction of Yama and of the world of the dead.
The Geometry
The three fires are arranged in a fixed geometric relationship within the sacrificial enclosure (vedi). The garhapatya is in the west; the is to the east, on a precisely measured line. The dakshinagni is to the south of the line connecting the other two. The Shulba Sutras (the geometrical Vedanga texts) specify the exact measurements — both the distances between the fires and the shapes and dimensions of the altars themselves. The geometric precision is held to be ritually necessary: a misshapen altar, or fires in the wrong relative position, would render the rite ineffective.
For the great somayāga ceremonies, an additional and far more elaborate altar is constructed — the uttara-vedi or "great altar," often in the form of a flying falcon (śyenacit) built up of precisely shaped bricks in five layers. The construction of this altar is one of the most extraordinary achievements of Vedic ritual mathematics, requiring sophisticated geometric calculation to ensure that the total area equals the prescribed value (often 7.5 square puruṣa-units, the height of a sacrificing priest).
The Daily Agnihotra
The most basic obligation of the is the agnihotra (अग्निहोत्र) — the twice-daily offering performed at sunset and sunrise. Hot milk is poured into the fire while the appropriate Yajurvedic mantras are recited. Two offerings in the morning (one before sunrise, one just at sunrise) and two in the evening (one just before sunset, one just after) are prescribed in the Shrauta Sutras. The agnihotra is described as the "daily payment of the cosmic debt" — the householder's contribution to maintaining the cosmic order through the linked acts of fire-offering and recitation.
Establishment and Maintenance
The fires are first established through an elaborate rite called the agnyādheya (अग्न्याधेय), traditionally performed at the householder's marriage or at a specific astrologically auspicious moment thereafter. Once established, they must be maintained by the householder personally. The flames may be transferred between the altars (the and the dakshinagni are kindled from coals taken from the garhapatya) but the fire substance itself must be continuous — the householder's fires must, in principle, descend in unbroken combustion from the moment of their first kindling.
At the householder's death, his own body is cremated using these three fires — they accompany him at last to the cremation ground. His son, who has inherited the obligation, then kindles his own new tretāgni from the household hearth-fire of his father's home.
Modern Survival
The full āhitāgni tradition has become rare but is not extinct. A small number of Nambudiri Brahmin families in Kerala, of Smārta Brahmins in Tamil Nadu, Karnataka, and Maharashtra, and of certain northern lineages continue to maintain the three fires. The 1975 Agnicayana ritual filmed by Frits Staal in Kerala — a full performance of the most elaborate Vedic sacrifice — required the participation of just such families. Each of these maintaining lineages constitutes, in the language of the tradition, an unbroken chain of fire descending from the Vedic age. The continuity is precarious, but for the moment the three fires of the Vedic priest still burn.