[citation needed] The older references uniformly indicate hotṛ as the presiding priest, with perhaps only the adhvaryu as his assistant in the earliest times.
[8] The rgvedic Brahmanas, Aitareya and Kausitaki, specify seven hotrakas to recite shastras (litanies): hotṛ, brāhmanācchamsin, maitrāvaruna, potṛ, neṣṭṛ, agnīdh and acchāvāka.
[citation needed] The requirements of the fully developed ritual were rigorous enough that only professional priests could perform them adequately.
[citation needed] In latter days, with the disappearance of Vedic ritual practice, purohita has become a generic term for "priest".
[citation needed] In the systematic expositions of the shrauta sutras,[9] which date to the fifth or sixth century BCE, the assistants are classified into four groups associated with each of the four chief priests, although the classifications are artificial and in some cases incorrect:[citation needed] Comparison with the sacred texts of Zoroastrianism, a distinct religion with the same origins, shows the antiquity of terms for priests such as *atharwan (Vedic atharvan; cognate to Avestan āθrauuan/aθaurun) and *zhautar (Ved.
However, a recent theory indicates that Proto Indo-Iranian *atharwan likely represents a substrate word from the unknown language of the BMAC civilization of Central Asia.
Though the meaning of *athar is unknown, Pinault speculates that it meant "superior force" and connects it to the Tocharian word for "hero".