Zoroastrianism, ancient pre-Islamic religion of Iran that survives there in isolated areas and, more prosperously, in India, where the descendants of Zoroastrian Iranian (Persian) immigrants are known as Parsis, or Parsees.

The Iranian prophet and religious reformer Zarathushtra (flourished before the 6th century BCE)—more widely known outside Iran as Zoroaster (the Greek form of his name)—is traditionally regarded as the founder of the religion.

Zoroastrianism contains both monotheistic and dualistic features. It likely influenced the other major Western religions—Judaism, Christianity, and Islam.

For a discussion of the context in which Zoroastrianism arose, see ancient Persian religion. The ancient Greeks saw in Zoroastrianism the archetype of the dualistic view of the world and of human destiny.

Zarathushtra was supposed to have instructed Pythagoras in Babylon and to have inspired the Chaldean doctrines of astrology and magic.

It is likely that Zoroastrianism influenced the development of Judaism and the birth of Christianity.

The Christians, following a Jewish tradition, identified Zoroaster with Ezekiel, Nimrod, Seth, Balaam, and Baruch and even, through the latter, with Jesus Christ himself.

On the other hand, as the presumed founder of astrology and magic, Zarathushtra could be considered the arch-heretic.

Though Zoroastrianism was never, even in the thinking of its founder, as insistently monotheistic as, for instance, Judaism or Islam, it does represent an original attempt at unifying under the worship of one supreme god a polytheistic religion comparable to those of the ancient Greeks, Latins, Indians, and other early peoples.

Its other salient feature, namely dualism, was never understood in an absolute, rigorous fashion. Good and evil fight an unequal battle in which the former is assured of triumph. God’s omnipotence is thus only temporarily limited.

In this struggle all human beings must enlist because of their capacity for free choice. They do so with soul and body, not against the body, for the opposition between good and evil is not the same as the one between spirit and matter.

Contrary to the Christian or Manichaean (from Manichaeism—a Hellenistic dualistic religion founded by the Iranian prophet Mani) attitude, fasting and celibacy are proscribed except as part of the purificatory ritual.

The human struggle has a negative aspect, nonetheless, in that it must strive for purity and avoid defilement by the forces of death, contact with dead matter, etc.

Thus, Zoroastrian ethics, though in itself lofty and rational, has a ritual aspect that is all-pervading. On the whole, Zoroastrianism is optimistic and has remained so even through the hardship and oppression of its believers.

Pre-Zoroastrian Iranian religion

The religion of Iran before the time of Zarathushtra is not directly accessible, for there are no reliable sources more ancient than those composed by or attributed to the prophet himself.

It has to be studied indirectly on the basis of later documents and by a comparative approach. The language of Iran is closely akin to that of northern India, and, hence, the people of the two lands probably had common ancestors who spoke a common Indo-Aryan language.

The religion of those peoples has been reconstructed by means of common elements contained in the sacred books of Iran and India, mainly the Avesta and the Vedas.

Both collections exhibit the same kind of polytheism with many of the same gods, notably the Indian Mitra (the Iranian Mithra), the cult of fire, sacrifice by means of a sacred liquor (soma in India, in Iran haoma), and other parallels.

There is, moreover, a list of Indo-Iranian gods in a treaty concluded about 1380 BCE between the Hittite emperor and the king of Mitanni. The list includes Mitra and Varuna, Indra, and the two Nāsatyas.

All of these gods also are found in the Vedas but only the first one in the Avesta, except that Indra and Nāñhaithya appear in the Avesta as demons; Varuna may have survived under another name.

Important changes, then, must have taken place on the Iranian side, not all of which can be attributed to the prophet.

The Indo-Iranians appear to have distinguished from among their gods the daiva (Indo-Iranian and Old Persian equivalent of Avestan daeva and Sanskrit deva, related to the Latin deus), meaning heavenly, and the asura, a special class with occult powers.

This situation was reflected in Vedic India; later on, asura came to signify, in Sanskrit, a kind of demon, because of the baleful aspect of the asura’s invisible power.

In Iran the evolution must have been different: the ahuras were extolled to the exclusion of the daevas, who were reduced to the rank of demons.

The reformation of Zarathushtra

Zarathushtra (Zoroaster) was a priest of a certain ahura (Avestan equivalent of Sanskrit asura) with the epithet mazdā, wise, whom Zarathushtra mentions once in his hymns with the [other] ahuras.”

Similarly, Darius I (522–486) and his successors worshipped Auramazda (Ahura Mazdā) and the other gods who exist or Ahura Mazdā, the greatest god.

The two historically related facts are evidently parallel: on both sides the rudiments of monotheism are present, though in a more elaborate form with the prophet Zarathushtra.

The Arsacid Period

In consequence of Alexander’s conquest, the Iranian religion was almost totally submerged by the wave of Hellenism.

At Susa, for instance, which had been one of the capital cities of the Achaemenids but where the religion of Auramazda was not indigenous, the coinage of the Seleucid and Arsacid periods does not represent a single Iranian deity.

Then the Iranian religion gradually emerged again. In Commagene in the middle of the 1st century BCE, gods bear combinations of Greek and Iranian names: Zeus Oromazdes, Apollo Mithra, Helios Hermes, Artagnes Herakles Ares.

The first proof of the use of a Zoroastrian calendar, implying the official recognition of Zoroastrianism, is found some 40 years earlier at Nisa (near modern Ashgabat in Turkmenistan).

By then some form of orthodoxy must have been established in which Auramazda and the entities (powers surrounding him) adjoin other gods such as Mithra, the Sun, and the Moon.

In Persis (modern Fārs), from the beginning of the Christian Era to the advent of the Sasanians (early 3rd century ce), any allusion to the fire cult disappears.

The coins seem to indicate, in not showing the fire altar, that the prince had lost interest in the Iranian religion.

The Sasanian period

With Ardashīr, the future founder of the Sasanian dynasty, the situation was different, and this may suggest that his religious zeal—as a hereditary priest of Staxr (Istaxr)—may have helped him seize power in his native province, even before he started attacking his Arsacid suzerain, Artabanus V.

Two persons are recorded, in different sources, as helping to establish Zoroastrianism under the first Sasanians: Kartēr and Tansar.

Whereas Kartēr is known through contemporary inscriptions, most of which were written by himself, Tansar (or Tosar) is only remembered in later books.

Post-Islamic Iranian Zoroastrianism

Islam won a decisive victory at al-Qādisiyyah in 635 over the armies of Yazdegerd III, the last Sasanid. Islam, in principle, tolerated the ancient religion, but conversions by persuasion or force were massive in many provinces.

Zoroastrianism fomented rebellion and brought persecutions upon itself. There were pockets of survival, notably in Persis, the ancient centre of the Achaemenian and Sasanian empires. Books were produced to save the essentials of the religion from a threatened disaster.

The disaster did occur, but exactly why and how is not known. Zoroastrians, called Gabars by the Muslims, survived in Iran as a persecuted minority in small enclaves at Yazd and Kerman.

The Parsis in India

From the 10th century onward, groups of Zoroastrians emigrated to India, where they found asylum in Gujarat. Their connection with their coreligionists in Iran seems to have been almost totally broken until the end of the 15th century.

Reestablished in 1477, the connection was kept up chiefly in the form of an exchange of letters until 1768. Under British rule, the Parsis, who previously had been humble agriculturists, started to enrich themselves through commerce, then through industry.

They became a most prosperous and modern community, centred in Bombay (Mumbai). Formerly they had adopted the Gujarati language and the dress of their Hindu milieu.

Later they adopted British customs, British dress, the education of girls, and the abolition of child marriage. In their enterprises as well as in their charities, they followed the example of the West.

From the 19th century on, they were able to help their less-favoured brethren in Iran, either through gifts or through intervention with the government.

God

Zarathushtra’s silence on Mithra is not easy to interpret. Since this god was closely associated with Varuna in India and with Varuna’s likely substitute in Iran, Zarathushtra can hardly have ignored one-half of this divine pair without a definite purpose.

Otherwise, it might be presumed that Mithra was included in the formula Mazdā and the [other] ahuras; however, Mithra is called in the Later Avesta (non-Gāthic) an ahura; so is Apām Napāt, a fire or brightness in the waters, corresponding to the Vedic Apam Napat.

As for Verethraghna (the entity or spirit of victory), it seems that since he took over the function of Indra, who was a daeva, he could not be called an ahura, but in order to mark his belonging to the world of ahuras he was called ahuradāta, “created by an ahura.”

It is in the framework of the religion of the ahuras, hostile to the cult of the daevas, that Zarathushtra’s message should be understood.

He emphasized the central importance of his god, the wise Ahura, by portraying him with an escort of entities, the powers of all the other gods, in an array against the forces of evil.

The moral dualism expressed in the opposition Asha–Druj (truth–falsehood) goes back at least to Indo-Iranian times, for the Veda knows it too, as rita-druh, though the contrast is not as sharply defined as in the Avesta.

Between these two principles, the Twin Spirits made an ominous choice, the Bounteous One becoming in thoughts, words, and deeds a partisan of Asha, ashavan, while the other became dregvant, partisan of the Druj.

After them it was the daevas’ turn, and they all chose wrongly. Ever since, the daevas have tried to corrupt each human being’s choice also.

To the army of the ashavans, headed by the Bounteous Spirit, was counter-posed the host of the dregvants, under the Destructive Spirit, Angra Mainyu.

Each combatant faced his exact counterpart: the Good Mind opposing the Bad Mind and Aramaiti being countered by Taromaiti.

In this battle the whole material universe is, through the entities, potentially enrolled, the Bounteous Spirit being the patron of humankind, Asha of fire, the Good Mind of the Ox, the Dominion of the metals, Aramaiti of the earth, Integrity and Immortality of the waters and plants.

Moreover, since the entities are at once divine and human (because both the spiritual and material qualities of man partake of divine), everyone faithful to the wise Ahura can commune with him.

After Zarathushtra, considerable changes occurred in the theology he had professed. The entities were reduced to mere deities, which were even separated into male and female. Never again were their names used to designate human faculties.

This is probably a consequence of the resurgence of the ancient gods.

Cosmogony

In the cosmogony as expounded in the Bundahishn, Ormazd (Ahura Mazdā) and Ahriman are separated by the void. They seem to have existed from all eternity, when Ahriman’s invidious attack initiates the whole process of creation.

The question of their origin is ignored, but it was implied, ever since Ormazd had taken the place of his Bounteous Spirit in the struggle against the Destructive Spirit.

Since Ahura Mazdā could no longer be the father of the two adversaries, the question of their origin was inevitable.

A solution was provided by Zurvanism: it is Zurvān (Time) who is the father of Ormazd and Ahriman. But this solution upset the very essence of Mazdaism and was therefore condemned as heretical.

Zurvanism was widely accepted, however, perhaps even prevalent, in Sasanian times. Traces of it are found in Mazdean orthodoxy, some features of which cannot otherwise be explained.

Cosmology

In order to vanquish Ahriman, Ormazd created the world as a battlefield. He knew that this fight would be limited in time—it would last 9,000 years—and he offered Ahriman a pact to that effect.

After they had created their respective material creations, Ahriman’s first attack was defeated by Ormazd with the help of the Ahuna Vairya prayer (the most sacred Zoroastrian prayer), and he lay prostrate for another period of 3,000 years, the second in a total of four.

He was then stirred up by the prostitute (Primal Woman) and went back to the attack, this time in the material universe.

He killed the Primal Bull, whose marrow gave birth to the plants and whose semen was collected and purified in the moon, whence it would produce the useful animals.

Ahriman then killed Gayōmart, the Primal Man, whose body produced the metals and whose semen was preserved and purified in the sun. A part of it would produce the rhubarb from which the first human couple would be born.

The first human couple was perverted by Ahriman, and it is only with the advent of Zarathushtra, after 3,000 years, that Ahriman’s supremacy came to an end.

Ormazd and Ahriman then fight on equal terms until Ormazd, at the end of the last 3,000 years, finally will triumph.

Humanity

The idea of a human being as a microcosm, already illustrated in the cosmogony, is further developed in the Bundahishn. As a result of the aggressor’s attack, each human being is mortal. But one does not die altogether.

There are five immortal parts of a human being: ahu (life), daēnā (religion), baodah (knowledge), urvan (soul), and fravashi (pre-existent souls). The latter term seems literally to mean “preeminent hero.”

The conception that caused this term to be applied to the manes (spirits) or pitarah of Iran is that of a defensive, protective power that continues to emanate from a chief even after death.

This originally aristocratic notion seems to have been vulgarized in the same way as, in Greece, any dead person came to be considered a hero, or, in Egypt, an Osiris.

Zarathushtra ignored the fravashi, but he was familiar with the daēnā. The latter term meant religion in both its objective and subjective senses.

Conclusion

Zoroastrianism is not the purely ethical religion it may at first seem.

In practice, despite the doctrine of free choice, Zoroastrians are so constantly involved in a meticulous struggle against the contamination of death and the thousand causes of defilement and against the threat, even in sleep, of ever-present demons that they do not often believe that they are leading their lives freely and morally.

Apart from this attitude, the belief in the power of destiny sometimes culminates in fatalism. The latter is easily associated with Zurvanism, itself sometimes tainted with materialism.

In the Mēnōk-i Khrat it is stated that though one be armed with the valor and strength of wisdom and knowledge, yet it is not possible to strive against fate.

On the whole, however, as the eminent historian of religions R.C. Zaehner notes, the theological premises of Zoroastrianism are based on an essentially moralistic view of life.

Britannica / ABC Flash Point News 2025.