Religion
Iranian religion in the pre-Achaemenian and Achaemenian periods is a subject on which there is little scholarly agreement. When the Iranians first entered the dim light of the protohistoric period, they were certainly polytheists whose religious beliefs and practices closely paralleled other Indo-Iranian and Indo-European groups at the same stage in history. Their gods were associated with natural phenomena, with social, military, and economic functions, and with abstract concepts such as justice and truth. Their religious practices included, among others, animal sacrifice, a reverence for fire, and the drinking of the juice of the haoma plant, a natural intoxicant.
Probably about 600 bc there arose in the northeast of the plateau the great Iranian religious prophet and teacher Zoroaster (Zarathushtra). The history of the religion that he founded is even more complicated and controversial than the history of pre-Zoroastrian Iranian religion. Yet certain features of his religious reform stand out. He was an ethical prophet of the highest rank, stressing constantly the need to act righteously and to speak the truth and abhor the lie. In his teaching, the lie was almost personified as the Druj, chief in the kingdom of the demons, to which he relegated many of the earlier Indo-Iranian deities. His god was Ahura Mazdā, who, it seems likely, was a creation, in name and attributes, of Zoroaster. Though in a certain sense technically monotheistic, early Zoroastrianism viewed the world in strongly dualistic terms, for Ahura Mazdā and the “Lie” were deeply involved in a struggle for the human soul. Zoroaster, as might be expected, attempted to reform earlier Iranian religious practices and beliefs. He first rejected and then perhaps allowed in a modified form the practice of the haoma cult, clearly condemned the practice of animal sacrifice, and elevated to central importance in the ritual a reverence for fire. Fire worship, however, is a misnomer, because the Zoroastrians have never worshiped fire but rather have revered it as the symbol par excellence of truth.
The crucial question is: Were the Achaemenids Zoroastrians or at least followers of the prophet in the terms in which they understood his message? Possibly Cyrus the Great was, probably Darius I was, and almost certainly Xerxes I and his successors were. Such a simple answer to the question is possible, however, only if it is understood that Zoroastrianism as a religion had already undergone considerable development and modification since Zoroaster’s lifetime, influenced by the beliefs and practices and by the religions of those people of the Middle East with whom the expanding Iranians had intimate contact.
The god of the Achaemenian kings was the great Ahura Mazdā, from whom they understood they had received their empire and with whose aid they accomplished all deeds. Xerxes and his successors mention other deities by name, but Ahura Mazdā remains supreme. Darius names only Ahura Mazdā in his inscriptions. More significant, however, is Darius’s tone, which is entirely compatible with the moral tone of Zoroaster and, in some instances, even compatible with details of Zoroaster’s theology. During the reigns of Darius and Xerxes, the archaeological record reveals that religious rituals were in force that were also compatible with an evolved and evolving Zoroastrianism. The haoma cult was practiced at Persepolis, but animal sacrifice is not attested. More important, fire clearly played a central role in Achaemenian religion.
There may have been religious overtones in the quarrel between Cambyses and Darius on the one hand and the false Bardiya—a magus, or Median priest—on the other. Certainly there were religious as well as political motivations behind Xerxes’ suppression of the daeva (deva) worshipers and the destruction of their temple. It is possible that there was some conflict among the royal Achaemenids, who were followers of one form of Zoroastrianism, the supporters of a different version of Zoroastrianism as practiced by other Iranians, believers in older forms of Iranian religion, and believers in foreign religions, which in the light of Zoroaster’s teachings were reprehensible. Compromises and syncretism, however, probably could not be prevented. Though the Zoroastrian calendar was adopted as the official calendar of the empire in the reign of Artaxerxes I, by the time of Artaxerxes II the ancient Iranian god Mithra and the goddess Anāhitā (Anahīti) had been accepted in the royal religion alongside Ahura Mazdā.
Thus, in a sense, the Achaemenian kings were Zoroastrians, but Zoroastrianism itself was probably no longer exactly the religion Zoroaster had attempted to establish. What the religion of the people beyond court circles may have been is almost impossible to say. One suspects that a variety of ancient Iranian cults and beliefs were prevalent. The magi, the traditional priests of the Medes, may have wielded more influence in the countryside than they did at court, and popular beliefs and practices may have been more deeply influenced by contact with other peoples and other religions. Later classical Zoroastrianism, as known in the Sāsānian period, was an amalgam of such popular cults, of the religion of the Achaemenian court, and of the teachings of the prophet in their purer form. (See also Zoroastrianism.)