Zoroastrianism: The Ancient Faith of Iran and the Ideas It Gave the World

Follows: The World's Religions, One Page Each and How the Sacred Texts Were Written. Companion pieces: the Religions long reads on Judaism, Christianity and Islam, and the Histories long read on Iran.

In Udvada, a small coastal town in Gujarat about 200 kilometres north of Mumbai, there is a fire that, by its community's tradition, has not gone out in well over a thousand years. Priests in white feed it sandalwood five times a day, at the five watches into which Zoroastrians divide the day and night. Pilgrims come from across India and Pakistan and from the diaspora to stand before it. If you are not a Zoroastrian you will not see it: in India, non-Zoroastrians are not allowed into any room from which the sacred fire can be seen.

The fire is called the Iranshah, "King of Iran". The name is the whole story in two words. The people who tend it, the Parsis ("Persians"), descend from Zoroastrians who left Iran after the Arab conquest of the 7th century. Their religion had been the faith of three Persian empires. Its prophet taught, perhaps three thousand years ago, that the world is a battleground between truth and the lie, that every person must choose a side, and that history will end with good's victory, the dead raised and the world made new. Those ideas, many scholars argue, travelled into Judaism, Christianity and Islam. Other scholars think the case is overstated. Either way, the religion that may have helped teach half of humanity to think about heaven, hell and a last judgement now has fewer members than a mid-sized town.

This long read tells that story: what Zoroastrians believe and do, how their scripture survived, what historians can and cannot say about their prophet, the much-debated question of their influence, and the hard choices facing the community in 2026.

A note on approach: this piece describes Zoroastrian belief in its own terms and sets the tradition's account beside what historians and philologists say, without ranking either. Zoroastrians themselves disagree on many points here, especially between traditionalists and reformists, and both are described.

In this long read

1. The prophet nobody can date
2. The Gathas and the Avesta: a scripture carried in memory
3. What Zoroastrians believe: one Wise Lord, truth and the lie, and the choice
4. Empire: the Achaemenid question (c. 550–330 BCE)
5. The Sasanian state church (224–651 CE)
6. Fire, purity and prayer: what Zoroastrians actually do
7. The end of days
8. Did Zoroastrianism shape Judaism, Christianity and Islam?
9. Conquest and the long decline in Iran (from 636 CE)
10. The Parsis of India, and the Iranis
11. The Towers of Silence and the vanishing vultures
12. Zoroastrians today: numbers, conversion and the future

Part 1 — The prophet nobody can date

The prophet's name in his own language was probably Zarathushtra. The Greeks, who had heard of him by the 5th century BCE, called him Zoroastres, and that became "Zoroaster" in Latin and English; Nietzsche brought the older form back into fashion. The name most likely contains the old Iranian word for camel, and is usually explained as "he who manages camels", though linguists have proposed other readings.

The tradition's account

Zoroastrian tradition, drawn from the Avesta and from much later Middle Persian books, tells a full life. Zarathushtra was born into the Spitama family, the son of Pourushaspa ("possessing grey horses") and Dughdova ("milkmaid"). He trained as a priest from childhood. At about thirty, at a spring festival, he went to a river at dawn and there met a shining being who revealed himself as Vohu Manah, "Good Mind", and led him into the presence of Ahura Mazda, the Wise Lord. From that vision came his teaching: there are two primal spirits, one good and one destructive, and humans must choose between them.

For years few listened, and the priests of the old religion opposed him. At about forty-two he won over a ruler named Vishtaspa and his queen, Hutaosa, and with royal protection a community grew. Tradition gives him three wives and six children and says he died at seventy-seven. Several accounts say he was murdered at an altar by a priest of the old religion; others say he died of old age.

What historians can say

Very little, with confidence. The only texts that may come from him are the Gathas, seventeen hymns preserved inside a later liturgy, and they are poems addressed to God, not a biography. Even his historical existence is not beyond question: some leading specialists, notably Jean Kellens and Prods Oktor Skjærvø, read the Gathas as ritual poetry and doubt that they let us recover an individual author at all. Most scholars still assume a real prophet-poet behind them.

The date is the famous problem. The Avesta itself gives no date, and the other evidence pulls in opposite directions.

The early date rests mainly on language. The Gathas' Old Avestan is so close to the Vedic Sanskrit of India's Rigveda that, for many linguists, the two cannot have been composed many centuries apart. Mary Boyce, the most influential 20th-century historian of the religion, put him somewhere between 1700 and 1000 BCE. The Encyclopaedia Iranica's general survey (by William Malandra, 2005) put it bluntly: the dating controversy has been a long-standing embarrassment, and if anything like a consensus exists, it is "ca. 1000 BCE give or take a century or so". Bruce Lincoln wrote in 1991 that the majority opinion inclined towards the end of the second millennium or the beginning of the first.

The honest summary: probably around 1000 BCE, possibly several centuries earlier, and almost certainly not as late as the Persian Empire.

Where he lived is uncertain too. The places named in the Avesta are in eastern Iran and Central Asia, and the texts never mention the western Iranian peoples, the Medes and Persians. The Iranica survey concluded that there is general agreement he did not live in western Iran, while attempts to pin him to one region of the east, such as Bactria (in today's Afghanistan), Sistan or Chorasmia, "remain tentative".

Part 2 — The Gathas and the Avesta: a scripture carried in memory

Zoroastrian scripture is called the Avesta. It is written in Avestan, an ancient Iranian language known from no other source, which survives in two stages: Old Avestan, the language of the Gathas and a few prayers, and Young Avestan, the language of everything else, which is several centuries later.

The Gathas

The Gathas are the heart of it. There are five, divided into seventeen hymns, with 238 stanzas in all, and they sit inside the long liturgy called the Yasna:

Between the first and second Gathas sits the Yasna Haptanghaiti, the "Yasna of seven chapters" (Yasna 35–41), in the same archaic language and probably nearly as old. Each Gatha has its own metre, and the poetry is dense, allusive and notoriously hard. Translations disagree widely, sometimes on the basic sense of a stanza, because Old Avestan survives in so few texts. That is one reason modern Zoroastrians can read the same hymns as stern ritual poetry or as a pure philosophical monotheism.

The rest of the Avesta

The Young Avestan texts include:

• The Yasna, the main liturgy, recited at the central ceremony (72 chapters, with the Gathas embedded in it).
• The Visperad, an extension of the Yasna for festivals.
• The Vendidad (Videvdad, "the law against the demons"), a priestly code of purity, pollution and penance, including the rules for disposing of the dead. Some reformist Zoroastrians reject its authority; traditionalists defend it.
• The Yashts, hymns to individual divine beings such as Mithra and the river goddess Anahita, full of old myths.
• The Khordeh Avesta, the "Little Avesta", the prayer book that ordinary Zoroastrians use.

How it survived

For most of its history the Avesta lived in memory. Priests learned the texts by heart and recited them in ritual, as Indian priests did the Vedas. It was written down only around the 5th or 6th century CE, under the Sasanian dynasty, using a new alphabet invented for the purpose, with far more letters than the Middle Persian script so that the sounds of the sacred recitation could be recorded exactly.

The tradition remembers a much larger book. According to Middle Persian texts, the full Avesta had twenty-one nasks ("books"), which Zarathushtra brought to Vishtaspa, and two master copies were kept until Alexander the Great burned one and scattered the other. Historians treat that story with caution: there is no evidence that a written Avesta existed in Achaemenid times, and the legend may reflect later priests' bitterness towards the Greek conqueror. What is clear is that the Sasanian edition was itself largely lost after the Arab conquest. The 9th- and 10th-century Zoroastrian commentators quote Avestan passages, and only about a quarter of the verses they cite can be found in what survives. The oldest surviving Avestan manuscript dates from 1323 CE.

Alongside the Avesta stand the Pahlavi books, works in Middle Persian written or revised mainly in the 9th and 10th centuries, after the conquest: the Denkard, an encyclopedia of the faith; the Bundahishn, on creation; the Arda Viraf Namag, a tour of heaven and hell. They are essential for understanding the developed religion, and they are also a problem for historians, because they were written down more than a thousand years after the Gathas. Their authority is itself a live question: traditionalist Parsis value them highly, while many Iranian and reformist Zoroastrians stress the Gathas alone.

A religion whose oldest hymns may be three thousand years old reached writing only in late antiquity, and its oldest surviving manuscript is younger than Dante.

Part 3 — What Zoroastrians believe: one Wise Lord, truth and the lie, and the choice

Ahura Mazda

At the centre is Ahura Mazda, "the Wise Lord": uncreated, wholly good, the creator of the world and of all that is good in it. In the Gathas, Zarathushtra addresses him directly, asking questions and seeking reassurance, in a tone that can feel startlingly personal. In Yasna 44 he asks a run of questions: who set the sun and stars on their paths, who holds up the earth and keeps the sky from falling, who made the waters and the plants. The implied answer is always the same: you, Wise Lord.

Truth and the lie

The moral world turns on two words. Asha (in Old Persian, arta) means truth, right order, the way things ought to be: cosmic order and moral rightness at once. Its opposite is druj, "the lie", deception and disorder. Asha is the single most frequent concept in the Gathas, appearing 157 times in their 238 stanzas.

The two spirits and the choice

The most quoted passage in Zoroastrian scripture is Yasna 30, where the prophet tells his hearers that at the beginning there were two spirits, twins, one better and one bad in thought, word and deed, and that between them the wise choose rightly and the foolish do not (Yasna 30.3, paraphrased). The good spirit is Spenta Mainyu, the "bounteous" or "holy" spirit; its opponent is Angra Mainyu, the destructive spirit, later known as Ahriman.

Everything follows from that choice. Evil is not part of God's creation and is not God's will. Human beings are free, and their choices matter cosmically: every good thought, word and deed strengthens the good creation, every evil one strengthens the lie. That is why the religion's best-known formula, recited daily, is three words: humata, hukhta, hvarshta, good thoughts, good words, good deeds.

The Amesha Spentas

Around Ahura Mazda stand the Amesha Spentas, the "bounteous immortals": aspects or emanations of God, each a quality to cultivate and, in later tradition, each the guardian of one part of creation.

That last column is a small sign of how deep the religion runs in Iranian culture: the official calendar of the Islamic Republic of Iran uses the month names of the Zoroastrian calendar, so every Iranian date carries old Zoroastrian divine names.

Below them are many yazatas, "beings worthy of worship", including Mithra, god of contracts and light, and Anahita, goddess of the waters.

Monotheism, dualism, or something else?

Is Zoroastrianism monotheistic? The question sounds simple and is one of the most argued in the field.

• The monotheist reading, held by most Zoroastrians today, says there is one God, Ahura Mazda; the Amesha Spentas are his aspects, the yazatas something like angels, and evil a destructive force with no creative power of its own. This reading was sharpened in the 19th century, when Scottish missionaries in Bombay, led by John Wilson, attacked the Parsis as dualists and polytheists, and the German scholar Martin Haug (1862) argued that Zarathushtra's original teaching in the Gathas had been a pure monotheism, later corrupted. Parsi reformers took up Haug's reading eagerly.
• The dualist reading stresses that evil in Zoroastrianism is real, independent and not created by God, which sets it apart from Judaism, Christianity and Islam. Some scholars call it "ethical dualism": one good God facing a real but ultimately doomed adversary.
• Many specialists now think both labels distort it. Skjærvø has described it as dualistic and polytheistic but with one supreme god, the father of the ordered cosmos; Almut Hintze and Kellens have argued that forcing the faith into Judeo-Christian categories hides what is distinctive about it.

Zoroastrians themselves are divided between traditionalists (mostly Parsis), who honour the whole inherited tradition including the Pahlavi books and the Vendidad, and reformists, who centre the Gathas and are more open to change, including on conversion.

Part 4 — Empire: the Achaemenid question (c. 550–330 BCE)

When Cyrus the Great united the Medes and Persians around 550 BCE and built the largest empire the world had yet seen, was it a Zoroastrian empire? Scholars still argue.

The case for. Darius I (ruled 522–486 BCE) begins his great inscription at Behistun by declaring that he is king by the favour of Ahuramazda, who granted him the kingdom, and he invokes Ahuramazda again and again. He presents the rebels he defeated as servants of "the lie", the evil the Gathas call druj, and his son Xerxes recorded that, by the favour of Ahura Mazda, he destroyed a sanctuary of the daivas and proclaimed that they must not be worshipped. Daeva is the very word the Gathas use for false gods. And the father of Darius was himself called Vishtaspa (Hystaspes), the name of the prophet's patron.

The case against. No Achaemenid inscription ever mentions Zarathushtra. Worship of Ahura Mazda is not proof of Zoroastrianism, since he may have been honoured in Iran before or apart from the prophet's reform. The kings were buried in rock-cut tombs at Naqsh-e Rustam and Pasargadae, which seems to break the later rule that corpses must not touch earth. And the Greek historian Herodotus, writing around 440 BCE, describes Persian religion without naming the prophet: the Persians, he says, set up no statues, temples or altars, and think those who do so foolish; they sacrifice on mountaintops to the whole circle of the sky, and to the sun, moon, earth, fire, water and winds (Histories 1.131).

Herodotus adds a detail that rings true to later practice. The bodies of Persians, he says, are not buried until a bird or a dog has torn them; this is certainly the way of the Magi, who make no secret of it, while other Persians coat the body in wax before burying it (Histories 1.140, Godley translation, 1920). The Magi were a Median priestly tribe, and they became the priests of the religion. Their name survives in a surprising place: through Greek magos and Latin magus, it is the root of the English word magic. And it is Magi, "wise men from the east", who come to Bethlehem in the Gospel of Matthew (2:1).

Most historians settle on something in between: by the Achaemenid period, a Zoroastrian form of Iranian religion had reached western Iran and the court, and it became a defining element of Persian culture, without yet being the codified, exclusive state religion it later became.

What the Achaemenids are most remembered for in religious history is not their own faith but their tolerance of others. Cyrus allowed the exiled Judeans in Babylon to return home and rebuild their temple, and the Hebrew Bible remembers him, uniquely for a foreign king, as God's "anointed" (Isaiah 45:1). That meeting of Persians and Jews is where the debate in Part 8 begins.

After Alexander destroyed the Achaemenid Empire in 330 BCE, Greek kings ruled Iran for a time. The Parthians (247 BCE–224 CE), an Iranian dynasty from the north-east, revived Iranian traditions, and Zoroastrian tradition credits one Parthian king, Valakhsh (probably a Vologases), with first trying to gather the scattered sacred texts. But the religion's great age of organisation came with the next dynasty.

Part 5 — The Sasanian state church (224–651 CE)

In 224 CE Ardashir, a ruler from Pars (Fars, the Persian homeland in south-west Iran), overthrew the Parthians and founded the Sasanian Empire, which for four centuries rivalled Rome and then Byzantium. The Sasanians made Zoroastrianism something it had perhaps never been before: an organised state church with a hierarchy, a fixed canon and the power to enforce orthodoxy.

Kartir: the priest who carved his own story in stone

The most vivid figure of this process is Kartir, a priest who served four kings in the 3rd century and rose to be the empire's chief religious authority. Unusually for a priest, he had his own inscriptions carved in rock, including one on the tower called the Ka'ba-ye Zartosht near Persepolis. In them he claims to have founded fire temples across the empire, appointed priests, and "struck down" the followers of other religions: Jews, Christians, Mandaeans, Buddhists and the followers of Mani, the prophet of Manichaeism, who died in prison under Bahram I in the 270s.

Historians read Kartir with care. As the historian Parvaneh Pourshariati has noted, it is not clear how far his declarations reflect what actually happened; Jewish and Christian sources of the time do not mention a persecution. Several Sasanian kings before and after were tolerant, and some Christians, especially the Church of the East, found long periods of favour. The Babylonian Talmud, one of Judaism's two great foundational works, was largely composed by rabbis living under Sasanian rule, and modern scholars have found traces of Persian law and culture in it.

Zurvan and Mazdak

Two movements show how much argument the state church contained.

• Zurvanism taught that behind both Ahura Mazda and Ahriman stood Zurvan, infinite Time, who fathered them as twins. Some scholars think it was the favoured theology of parts of the Sasanian court; others see it as one current among several. Orthodox Zoroastrians came to reject it, because it made good and evil equal brothers and put a neutral principle above the Wise Lord.
• Mazdak, a reforming priest of the late 5th and early 6th centuries, preached a radical egalitarianism, including the sharing of property, and won the backing of King Kavad I for a time, until Kavad's son Khosrow, later Khosrow I, crushed the movement and had its leaders killed.

What the state church built

The Sasanian centuries gave the religion much of the shape it still has: the written Avesta in its new alphabet; the grades of sacred fire; the great royal fire temples; a calendar of festivals; a system of law on purity, marriage and inheritance; and a society formally divided into ranked estates of priests, warriors, commoners and artisans. Much of what we know of it comes from the Pahlavi books written soon after the empire fell, which look back on it as a golden age.

The Sasanian Empire gave Zoroastrianism its canon, its clergy and its power. When the empire fell, the religion lost its protector at a stroke.

Part 6 — Fire, purity and prayer: what Zoroastrians actually do

Outsiders often call Zoroastrians "fire worshippers". Zoroastrians reject the phrase. Fire is not God; it is the purest of Ahura Mazda's creations, the visible sign of truth and light, the presence before which one prays. Zoroastrians also pray facing the sun, the moon or a lamp.

A day

A devout Zoroastrian's day is framed by the kusti ritual. Every Zoroastrian who has been initiated wears two sacred garments: the sudreh (sedreh), a white cotton undershirt, and the kusti, a long cord of 72 fine white woollen threads, one for each chapter of the Yasna, wound three times around the waist and knotted at front and back. Each morning, after washing and before prayers, and again at other times of prayer through the day, the believer unties and reties the kusti while reciting short prayers, facing a source of light. The ritual takes a few minutes. It is a small daily renewal of the choice in Yasna 30: rejecting the destructive spirit and re-binding oneself to the good.

The day is divided into five gahs, watches of prayer, from sunrise to the dead of night. The most loved prayers are short and, for most believers, recited in Avestan whether or not they understand every word: the Ashem Vohu, praising asha, and the Ahuna Vairya (Yatha Ahu Vairyo), the holiest prayer of all, which may originally have been the opening stanza of the first Gatha.

Fire temples

A fire temple houses one of three grades of sacred fire:

The highest-grade fires must never go out. Priests tend them five times a day in a ceremony called the boi, offering sandalwood and reciting prayers.

The great ceremony

The central ritual is the Yasna, a long liturgy performed by priests in an inner ritual space, in which the whole Yasna text is recited and a drink called haoma (the Iranian counterpart of the Vedic soma) is prepared and consecrated. Only fully qualified priests can perform it.

Priests

Zoroastrian priesthood is hereditary. In India, priests come from priestly families (the athornan) and are men. An ervad has completed the first stage of initiation; a mobed can perform the higher ceremonies; a dastur is a senior high priest. In 2011, the council of priests in Tehran announced that women had been certified, for the first time, as mobedyar, assistant priests able to perform some ceremonies, in Iran and North America. Indian traditionalists have not followed.

Rites of life

• Navjote (in India) or sedreh-pushi (in Iran): the initiation, typically between about seven and twelve, at which a child, having learned the daily prayers, puts on the sudreh and kusti and performs the kusti ritual for the first time. Many Zoroastrians describe it as the moment the child chooses the faith for themselves.
• Marriage, celebrated with Indian and Iranian customs that vary by community.
• Death, with purity rules strict enough to have their own Part 11.

Purity

Behind much of the practice lies the idea of purity. Death, decay and disease are the work of the destructive spirit; the good creations, above all fire, water and earth, must be protected from them. A corpse is the most powerful source of pollution, which is why it must not be burned (polluting fire), buried (polluting earth) or put in water. Some reformists see these rules as ancient public hygiene; traditionalists see them as sacred law.

The year

The calendar's great feasts are the six gahambars, seasonal festivals once tied to the farming year and marked by communal meals, and Nowruz, the new year at the spring equinox. Nowruz has long since outgrown its Zoroastrian roots: it is celebrated, mostly as a secular holiday, by many millions of people of every faith from the Balkans to Central Asia, and it remains a holy day for Zoroastrians. At the last festival of the old year the fravashis, the guardian spirits of the dead, are believed to return to their old homes, and they are welcomed with prayers and offerings.

Part 7 — The end of days

Zoroastrianism has a fully worked-out account of what happens after death and at the end of time. Its outline appears in the Gathas, which speak of a bridge, of reward and punishment, and of a final "making wonderful"; the full drama is spelled out in the Pahlavi books of the 9th and 10th centuries.

The individual: the Chinvat Bridge

After death, the soul comes to the Chinvat Bridge, the "bridge of the separator". There its deeds are weighed by divine judges, Mithra, Sraosha and Rashnu. The soul then meets its own conscience, its daena, in human form. For the righteous she is a beautiful young woman, sweet-smelling, who leads the soul across a bridge that widens to let it pass into the House of Song. For the wicked she is a foul old hag, and the bridge narrows to a blade's edge, so that the soul falls into the House of the Lie. Those whose good and evil deeds are exactly balanced wait in a neutral place, Hamistagan.

Two features stand out. The judgement is purely on one's own thoughts, words and deeds; no one else can save you. And hell is not eternal. Its punishments are real but temporary, a purgation rather than a final destination. Some modern Zoroastrians read the bridge itself as a picture of the choices one makes in life rather than a physical place.

The world: the renovation

History, in the developed tradition, runs in great cycles of 3,000 years. In the last age, as evil makes its final assault, three saviours called Saoshyants will be born, one every thousand years, each conceived miraculously from the seed of Zarathushtra preserved in a lake. The last Saoshyant will raise the dead. Then comes the final judgement: all humanity must pass through a river of molten metal, which to the righteous will feel like warm milk and which will purify everyone else. Evil will be defeated for ever; the mountains will be levelled, the world made perfect, and all humanity will live forever with Ahura Mazda in body and soul. The word for this is frashokereti, the "making wonderful" of the world.

That table is the reason Zoroastrianism matters far beyond its own community, and the reason for the argument in the next part.

Part 8 — Did Zoroastrianism shape Judaism, Christianity and Islam?

This is one of the most interesting questions in the history of religion, and one of the most often overstated. The library's one-page survey says simply that Zoroastrian ideas influenced later Abrahamic concepts of heaven, hell and judgement. Many scholars agree. Others think the case is far weaker than it sounds. Here are both, at their strongest.

The case for influence

The timing fits. The Hebrew Bible's older books have almost no developed afterlife: the dead go down to Sheol, a shadowy pit. The ideas of a cosmic adversary (Satan), angels with names and ranks, a final judgement and the resurrection of the dead appear in Jewish texts after the Persian conquest of Babylon in 539 BCE, when Jews lived for two centuries as subjects of a Persian empire, and they become prominent in the Second Temple period. The first clear statement of bodily resurrection in the Hebrew Bible comes in the Book of Daniel, usually dated to about 164 BCE: "many of them that sleep in the dust of the earth shall awake, some to everlasting life, and some to reproaches and everlasting abhorrence" (Daniel 12:2, JPS 1917).

The contact is documented. Persian rulers freed the exiles and funded the rebuilding of the Temple; the Bible praises Cyrus as God's anointed (Isaiah 45:1) and quotes a decree of Cyrus (Ezra 1:2–3). Some of the latest books of the Bible use Persian loanwords, among them pardes, an enclosed garden, from Old Iranian, which reached Greek as paradeisos and English as "paradise". Later, rabbis compiled the Babylonian Talmud under Sasanian rule.

The pattern is coherent. Mary Boyce, in Zoroastrians: Their Religious Beliefs and Practices (1979), argued that Zarathushtra was the first to teach individual judgement, heaven and hell, the resurrection of the body, the last judgement and everlasting life, and that these became familiar to much of mankind through borrowing by Judaism, Christianity and Islam, while finding their fullest logical coherence in Zoroastrianism itself. Norman Cohn's Cosmos, Chaos and the World to Come (1993) made the broader case that Zarathushtra broke with the ancient world's static picture of order endlessly threatened by chaos, and imagined history moving towards a final victory of good, a vision later taken up by Jewish apocalyptic groups and the early Christians.

The case against, or for caution

The dating problem. The detailed Zoroastrian accounts of resurrection, saviours and the end of the world are found in Pahlavi books of the 9th and 10th centuries CE, written after Christianity and Islam already existed. The Gathas contain only hints. So when a Pahlavi text and a Christian text agree, who borrowed from whom? It is possible that some influence ran the other way, or that both drew on shared ideas of the ancient Near East.

The evidence is circumstantial. In an influential 1985 article in the Journal of the American Academy of Religion, "The Question of Religious Influence", the Old Testament scholar James Barr argued that resemblance is not proof of borrowing; that the Jewish developments can often be explained from inside Israel's own tradition and its other neighbours; and that scholars on both sides had been too quick to assume what they wanted to find.

Other routes. Some scholars point to Greek thought, through Hellenism, as at least as important: the immortality of the soul, for example, owes more to Plato than to Zarathushtra. Others note real differences: Zoroastrian evil is independent of God, whereas in Judaism even Satan is a servant in God's court, as in the Book of Job.

Where the debate stands

Most scholars today take a middle position. The historian Lester Grabbe has written that there is general agreement that Persian religion had its influence on Judaism over the centuries, and that the real question is where, and which developments can be ascribed to the Iranian side rather than to Greek or other cultures. In other words: influence is likely; its exact scope is unproven.

The most defensible sentence is this one: Persian religion was in the room when Judaism developed its ideas about the end of time, and nobody can yet prove exactly what it said.

For Islam, the question is different. Muslims came to treat Zoroastrians as a protected "People of the Book" (Part 9), and Islamic thought absorbed much of Persian culture. Some scholars have proposed Persian echoes in Islamic images such as the bridge over hell; others regard such parallels as common heritage of the region. Muslims, for their part, understand Islam's teachings as revealed, not borrowed.

Part 9 — Conquest and the long decline in Iran (from 636 CE)

In the 630s the armies of the new Islamic caliphate, fresh from the Arabian peninsula, struck a Sasanian Empire exhausted by decades of war with Byzantium. The Arabs won at al-Qadisiyyah (in the mid-630s) and took the capital, Ctesiphon; at Nahavand in 642 the last great Sasanian army was destroyed. The last king, Yazdegerd III, fled east and was killed near Merv in 651, by tradition by a miller.

How Iran became Muslim

Iran did not convert overnight, and mostly not by the sword. Because Zoroastrians were so numerous, Muslim jurists came to classify them, with some hesitation, among the dhimmi, protected non-Muslims who could keep their religion in exchange for a poll tax, the jizya, and acceptance of a lower status. At first there was little pressure to convert. Over time the pressures accumulated: the jizya, exclusion from power, and social and economic advantages that lay with Muslims. Nobles and city-dwellers converted first, peasants later. The historian Richard Bulliet's well-known "conversion curve", reconstructed from the spread of Muslim names in medieval biographical records, suggests that Muslims were perhaps a tenth of Iran's population under the Umayyad caliphs, about 40 percent by the mid-9th century and nearly 80 percent by the end of the 11th.

There was also violence and humiliation. In the 9th century a famous cypress in Khorasan, said in legend to have been planted by Zarathushtra himself, was cut down for a caliph's palace. In Bukhara, according to one account, the Arab governor converted the city several times before it stayed converted, turning the fire temple into a mosque and paying people to attend Friday prayers. Medieval Zoroastrian texts look back on this as an age of grief.

Survival on the desert's edge

Zoroastrians gathered where they could be inconspicuous, especially in Yazd and Kerman, oasis cities on the edge of Iran's great salt deserts, which remain the heart of Iranian Zoroastrianism. Yazd became the seat of the Iranian high priests. Muslims called them gabr, a contemptuous word for infidel. Their Persian-derived dialect, called Dari or Behdini ("of the Good Religion"), still survives among them.

Meanwhile, Zoroastrian priests did something crucial: in the 9th and 10th centuries they wrote down their tradition in the Pahlavi books, many of them written expressly to encourage the faithful to stand firm. And Iranian Muslim culture kept the old stories alive. Around 1010, the poet Ferdowsi completed the Shahnameh, the "Book of Kings", Iran's national epic, full of the legendary kings and heroes of Zoroastrian tradition. In a 16th-century letter to their co-religionists in India, the priests of Yazd lamented that no period, not even Alexander's, had been as hard for the faithful as this "millennium of the demon of Wrath".

The 19th and 20th centuries

Conditions in Qajar Iran (1789–1925) were often harsh. Help came from India. In 1854 the Parsi philanthropist Dinshaw Maneckji Petit founded the Persian Zoroastrian Amelioration Fund, which sent an emissary, Maneckji Limji Hataria, to Iran. He opened schools, organised community councils and campaigned for the community's rights; in 1882 the jizya on Iranian Zoroastrians was finally remitted, a step his campaigning may have helped bring about.

The Pahlavi shahs (1925–1979) celebrated Iran's pre-Islamic past as part of their nationalism, and Zoroastrians prospered. The Islamic Republic's constitution of 1979 recognises Zoroastrians, Jews and Christians as the only official religious minorities, free "within the limits of the law" to perform their rites and follow their own rules in personal matters (Article 13), and reserves one seat in parliament for a Zoroastrian (Article 64). Conversion from Islam, however, is not recognised and is legally dangerous, so the community cannot accept Iranian Muslims who want to join it.

Part 10 — The Parsis of India, and the Iranis

The story of Sanjan

The Parsis' founding story is told in a Persian poem, the Qissa-i Sanjan ("Story of Sanjan"), written by a priest named Bahman Kaikobad in 1599 or 1600, many centuries after the events it describes. It tells how, after the fall of the Sasanians, a group of the faithful left Khorasan, stayed for years at the island of Diu off the Indian coast, survived a storm at sea and landed in Gujarat. They asked the local Hindu ruler, Jadi Rana, for refuge. He asked them to explain their faith and set conditions: they should adopt the local language, their women should dress like local women, they should lay down their weapons, and their weddings should take place in the evening. They agreed, settled at Sanjan, and in time consecrated a sacred fire there.

Many Parsis also tell a story that is not in the poem: that the king sent the newcomers a bowl full to the brim with milk, meaning that his land was full, and that their priest stirred in sugar without spilling a drop, to show that they would sweeten the community without overflowing it. It is folklore, and it is the best-loved image Parsis have of themselves.

When did they land? The poem is vague and contradictory about elapsed time, and scholars have proposed 716, 785 and 936 CE, among other dates; arguments over the date have long been fierce within the community. Historians also note that the poem is the only account, and that trade between Iran and India's west coast long predates the conquest; persecution alone may not explain the migration.

Later, Sanjan was sacked, probably in 1465, and the refugees carried the sacred fire into the hills, then to Navsari, and finally, in the 1740s, to Udvada, where the Iranshah fire from this piece's first paragraph burns today.

Bombay

For centuries the Parsis were farmers, weavers, traders and priests in Gujarat. Their fortunes changed with the British. The East India Company settled first at Surat and then at Bombay (Mumbai), and Parsis became brokers, shipbuilders and merchants for it. In 1728 the community founded the Bombay Parsi Punchayet to govern its affairs. British schools gave Parsi boys and girls an early modern education, and by the 19th century Parsis were among the most prominent communities in India: industrialists like Jamsetji Tata, often called the father of Indian industry, and the Godrej and Wadia families; Dadabhai Naoroji, an early leader of the Indian national movement; later, the nuclear physicist Homi J. Bhabha and the conductor Zubin Mehta.

Wealth flowed back into the community and the faith: fire temples, hospitals, schools and housing colonies, and the funds that helped the Zoroastrians of Iran.

The Iranis

India has a second Zoroastrian community, the Iranis: descendants of Zoroastrians who came from Iran much later, mostly in the 19th and early 20th centuries, escaping poverty and discrimination under the Qajars. They kept a stronger Iranian identity and dialect, and they are famous for the Irani cafés they opened in Mumbai, Pune and Hyderabad, known for their Irani chai; Mumbai had about 350 in the 1950s and only about 25 by 2005. Today the two communities intermarry and share temples, but the distinction is still felt.

Part 11 — The Towers of Silence and the vanishing vultures

On Malabar Hill, one of the most expensive neighbourhoods of Mumbai, there is a large forested estate called Doongerwadi. Inside stand the city's Towers of Silence (dakhmas): low, round, roofless stone towers. A Parsi body is carried there by a special class of pallbearers, laid on the platform, and left to the sun and the birds. The platform has three rings, for men, women and children; once the bones have been bleached dry, they are swept into a central pit, where they crumble, with lime, into dust.

Why exposure

The logic follows from the purity rules in Part 6. A corpse is the most polluting thing there is; burying it pollutes the earth, burning it pollutes fire, putting it in water pollutes water. Exposure lets the body be consumed without defiling any of the good creations. Parsis also describe it as a final act of charity: giving one's body to the birds. Herodotus saw something like it among the Magi in the 5th century BCE, but the towers themselves are much later: they are first documented in Zoroastrian texts of the 9th century CE. Iranian Zoroastrians gave them up in the 20th century, moving to burial in cemeteries with cement-lined graves; in India the towers remain in use.

The collapse

The system depended on vultures, and in the 1990s the vultures of South Asia began to die. In just over a decade, populations of the white-rumped vulture, once one of the most common large birds of prey in the world, fell by more than 95 percent. In 2004 a team led by Lindsay Oaks of The Peregrine Fund published the cause in Nature: diclofenac, a cheap painkiller given to cattle, which caused fatal kidney failure in vultures that ate the carcasses. India banned veterinary diclofenac in 2006, and the decline has slowed, but the birds that once cleared a body in hours are almost gone.

The consequences went far beyond the Parsis. In a 2024 paper in the American Economic Review, economists Eyal Frank and Anant Sudarshan estimated that the functional extinction of India's vultures, by leaving carcasses to rot and feral dogs to multiply, increased human mortality by more than 4 percent, with damages they valued at $69.4 billion a year.

What the community did

For Parsis the question became urgent and painful. Bodies in the towers now took months to decompose. The community has tried large solar concentrators (mirrors) to speed decomposition, which work poorly in the monsoon, and in 2002 asked bird-of-prey specialists for help with vulture breeding. Some families now choose cremation or burial, which traditionalists regard as forbidden. Who may use the towers is itself disputed: the trusts that manage them often refuse the children of mixed marriages. Traditionalists insist the towers remain the only proper way; reformers argue that the deeper purpose, protecting the good creation and honouring the dead, can be met in other ways.

A ritual designed to protect the good creation from death now depends on the survival of a single bird, and the bird was killed by a medicine meant to heal cows.

Part 12 — Zoroastrians today: numbers, conversion and the future

How many?

Counting Zoroastrians is surprisingly hard. The best worldwide count is a demographic survey compiled for the Federation of Zoroastrian Associations of North America (FEZANA) in 2012. It gave a world total of 111,691 using the community's own estimate of 15,000 for Iran, or 121,962 using the Iranian census figure of 25,271, and warned that it was not a rigorous census.

A note of caution on Iran. A 2020 online survey by GAMAAN, a Netherlands-based research group, found that 8 percent of weighted respondents in Iran called themselves Zoroastrian. The researchers who analysed it, in a 2023 article, called this "survey Zoroastrianism": an expression of Iranian identity and protest against the Islamic Republic, not membership in the historic community, which is far smaller.

The decline is real. India's Parsi population has fallen steeply since the mid-20th century, and the community is old: it marries late, has few children, and has seen many of its young people emigrate. Deaths outnumber births by a wide margin.

The conversion debate

This is the question that divides the community most deeply.

Traditionalists, especially among the Parsis, hold that one is born a Zoroastrian. In their view the Parsis are an ethno-religious community, like the Jews, whose identity was preserved for over a thousand years in India precisely by not accepting converts, and the promise made at Sanjan not to proselytise is part of that history. Many also hold that only children of a Parsi father may be initiated, a rule that falls hardest on Parsi women who marry outside the community, whose children may be refused navjote and who may themselves be barred from fire temples and the Towers of Silence. Traditionalists see these rules as the walls that kept the community alive.

Reformists, more common in Iran and the diaspora, argue that the Gathas speak to all humanity, that Zarathushtra himself made converts, that older Zoroastrian authorities allowed conversion, and that a community of ageing families cannot survive by closing its doors. Many accept the children of mixed marriages through either parent, and some accept adult converts. Iran's council of priests in Tehran endorses conversion in principle, though Iranian law forbids Muslims to convert.

In practice, the boundary is moving. In North America and Europe, many associations welcome mixed families. New communities of converts have appeared, notably among Kurds in Iraqi Kurdistan, where some turned to Zoroastrianism after the war with the Islamic State, and in Sweden. Claims about their number vary widely: estimates of new converts in 2015 alone ranged from 10,000 to 100,000 (US Commission on International Religious Freedom, 2017); in 2019 the community's representative to the regional government said more than 10,000 were registered, while an academic in Sulaimani called "at least several thousand" a conservative estimate. None of these figures has been independently confirmed. Many born Zoroastrians welcome them; others doubt that they are joining the same religion.

A famous son

The most famous person of Zoroastrian heritage in modern times was probably born Farrokh Bulsara in Zanzibar in 1946, to Parsi parents from Gujarat. The world knew him as Freddie Mercury of Queen. He rarely spoke about his background, though it was part of the boarding-school childhood in India that shaped him, and when he died in 1991 his funeral in London was conducted by a Zoroastrian priest. Parsis tend to mention him with a mixture of pride and gentle amusement, which seems the right spirit.

Open questions

• Who belongs? Birth, choice, father, mother, or the Gathas' universal call.
• Which texts rule? The Gathas alone, or the whole inherited tradition including the Vendidad and the Pahlavi books.
• What to do with the dead? Towers without vultures, cremation, or burial.
• Can women be priests? Iran and North America have begun; India has not.
• How to survive? With roughly 120,000 members by the best count, the community faces a question few religions ever face: whether it will exist at all in a century.

The takeaway

Zoroastrianism grew from hymns composed, most scholars think, around 1000 BCE by a priest-poet in eastern Iran, carried in memory for perhaps fifteen centuries before they were written down. It taught that one Wise Lord stands against a real but doomed evil, that every person chooses a side through good thoughts, words and deeds, and that history will end in judgement, resurrection and a renewed world. It became the faith of Persian empires and an organised state church under the Sasanians, then declined over centuries of Muslim rule in Iran, while a small group of refugees preserved it in India. Its ideas may have helped shape Judaism, Christianity and Islam, though how much is still argued. Today it is a community of roughly 110,000–125,000 people, divided over conversion and the dead, and still feeding the same fires.

Try this: for one day, take the religion's three-word formula as an experiment. Each evening, ask yourself one question for each word: what was one good thought, one good word and one good deed today, and what was its opposite? Then notice what Zoroastrians notice: that the choice comes back every few hours, and that it is never made once and for all.

Sources & Further Reading

Sources
- Wikipedia, "Zoroaster", "Zoroastrianism", "Gathas", "Avesta", "Amesha Spenta", "Parsis", "Qissa-i Sanjan", "Tower of Silence", "Fire temple", "Atash Behram", "Iranshah Atash Behram", "Kartir", "Zurvanism", "Maneckji Limji Hataria", "Battle of Nahavand", "Yazdegerd III", "Indian vulture crisis", "Freddie Mercury", "Solar Hijri calendar" (consulted 31 October 2026 as leads, with the scholarly works they cite: Boyce, Malandra (Encyclopaedia Iranica, 2005), Kellens, Lincoln, Skjærvø, Hintze, Grabbe, Pourshariati). Encyclopaedia Iranica itself could not be fetched directly.
- Yasna translation: L. H. Mills and C. Bartholomae/I. J. S. Taraporewala as presented on avesta.org (Gathas paraphrased in this piece rather than quoted).
- Herodotus, Histories 1.131 and 1.140, trans. A. D. Godley (1920), Perseus Digital Library.
- The Qissa-i Sanjan, trans. S. H. Hodivala, Studies in Parsi History (Bombay, 1920), avesta.org edition.
- Daniel 12:2, Isaiah 45:1, Ezra 1:2–3: The Holy Scriptures (JPS, 1917), via Sefaria.
- James Barr, "The Question of Religious Influence: The Case of Zoroastrianism, Judaism, and Christianity", Journal of the American Academy of Religion 53:2 (1985), 201–236.
- Norman Cohn, Cosmos, Chaos and the World to Come (Yale University Press, 1993; 2nd ed. 2001), publisher's description.
- J. L. Oaks et al., "Diclofenac residues as the cause of vulture population decline in Pakistan", Nature 427 (2004).
- Eyal Frank and Anant Sudarshan, "The Social Costs of Keystone Species Collapse: Evidence from the Decline of Vultures in India", American Economic Review (October 2024), abstract.
- Roshan Rivetna, "The Zarathushti World: A 2012 Demographic Picture", FEZANA Journal (Fall 2013), population table.
- Immigration and Refugee Board of Canada, Response to Information Request IRQ106299.E, "Iraq: Conversion to Zoroastrianism in the Kurdistan Region of Iraq" (3 July 2019), citing USCIRF (May 2017) and interviews.
- European Union Agency for Asylum, COI Query Response, "Iran: Situation of individuals who have converted from Islam to Zoroastrianism" (May 2025).
- Constitution of the Islamic Republic of Iran (1979, rev. 1989), Articles 13 and 64, via the Constitute Project.
- M. Stausberg, P. Tamimi Arab and A. Maleki, "Survey Zoroastrians: Online Religious Identification in the Islamic Republic of Iran", Journal for the Scientific Study of Religion 62:4 (2023), as cited by EUAA.

Go deeper
- 📘 Zoroastrians: Their Religious Beliefs and Practices — Mary Boyce (the classic one-volume history, from the prophet to the modern Parsis; strong on practice, and the boldest statement of the influence thesis)
- 📘 Zoroastrianism: An Introduction — Jenny Rose (a clear, current introduction that is careful about what the evidence can and cannot show)
- 📘 The Wiley Blackwell Companion to Zoroastrianism — Michael Stausberg and Yuhan Sohrab-Dinshaw Vevaina (eds.) (the scholarly state of the field, chapter by chapter, for readers who want the debates in full)
- 📘 Cosmos, Chaos and the World to Come — Norman Cohn (the influence argument told as a sweeping history of the idea of the end of the world; read it alongside Barr's critique)
- 🌐 Avesta — Zoroastrian Archives (translations of the Avesta, the Qissa-i Sanjan and much else, compiled by Joseph H. Peterson)
- 🌐 Companion pieces in this library: The World's Religions, One Page Each, How the Sacred Texts Were Written, Pilgrimage: Why Humans Walk to Holy Places, and the Religions long read Judaism: A People, a Covenant and a Conversation Across 3,000 Years