THEAvesta (from pahlavi abestāg) is the set of sacred texts of the Mazdean religion and forms the sacred book, the priestly code of the Zoroastrians. He is sometimes known in the West under the mistaken name of Zend Avesta. It is written in several states of ancient Iranian, referred to as avestic. The oldest parts, those of the gathas, are in a language as archaic as that of Rig Veda (Vedic Sanskrit), "Gathic", the others in late Avestic. Everything is written in the Avestic alphabet.