Persian Religion and Philosophy: From Zoroastrianism to the Sasanian Renaissance

The Magi of the Gospel of Matthew travelled from the East to Bethlehem. The cult of Mithras spread from the Iranian plateau to Roman Britain. The Shahnameh of Ferdowsi, the longest poem ever written in any language, opens with a Zoroastrian cosmology. The medieval Latin West learned Aristotle from an Arabic chain that ran through Baghdad, Basra, and the Sasanian Academy of Gondeshapur. None of this is incidental to the study of the Persian Empire. Religion was the central pillar of Persian civilisation, and the philosophical and scientific tradition that grew up inside it was, in its origins, the synthesis of Greek, Indian, and Iranian thought achieved in the Sasanian period.

Two things are usually said about this inheritance. Both are partly wrong. The first is that Zoroastrianism is the “state religion” of pre-Islamic Iran, cleanly transmitted from Zarathustra to the Sasanian collapse. The second is that the philosophy of the Islamic world is essentially Greek, with the Persian contribution reduced to translation. The truth in each case is more tangled, and the tangles are the interesting part. The principal modern scholarship is Mary Boyce’s three-volume History of Zoroastrianism (1975–1991, the last volume completed by Frantz Grenet after Boyce’s death), Gherardo Gnoli’s Zoroaster’s Time and Homeland (1980) and The Idea of Iran (1989), Jean Kellens’ Essais zoroastriens (2011), Shaul Shaked’s Dualism in Transformation (1994), Prods Oktor Skjærvø’s The Spirit of Zoroastrianism (2011), James Russell’s Zoroastrianism in Armenia (1987) and his many essays, and the relevant fascicles of the Encyclopaedia Iranica and the Cambridge History of Iran. What follows is a synthesis, with the disagreements named.

The Indo-Iranian substrate

The religions of the Iranian world are rooted in the shared Indo-Iranian religious tradition of the Bronze Age, a complex of beliefs, rituals, and mythologies that the proto-Indo-Iranian peoples carried with them as they moved across the steppes of Central Asia in the third and second millennia BCE. The Vedic religion of early India and the pre-Zoroastrian religion of the Iranian Plateau share a common vocabulary. The names of the gods Indra, Mitra, Varuna, and Nasatya appear in both the Rig Veda and the older strata of the Avesta. The daeva cult of the Vedas, however, was demonised in the Zoroastrian tradition, and the asura of the Vedas (originally a title of the highest gods) became the ahura of the Zoroastrian — a complex inversion of meaning that Boyce and Gnoli treat as one of the distinctive marks of the Iranian tradition.

The Indo-Iranian background also explains the prominence in Persian religion of asha (truth, order, the cosmic law), druj (the lie), haoma (the sacred drink), and the ritual of fire. All appear in both Vedic and Iranian sources, but the Iranian tradition gave them a sharper ethical edge and a more consistent metaphysical structure. The cult of fire became the most distinctive visual marker of Persian religion, surviving the Arab conquest and continuing, in the Zoroastrian community of Iran and the Parsi diaspora, into the present.

Zarathustra and the question of dates

The single most important event in the history of Persian religion is the prophetic career of Zarathustra, a figure whose historicity, dates, and even homeland have been debated for more than a century. The traditional Zoroastrian dating places him in the sixth century BCE; the linguistic evidence of the Gathas, the seventeen hymns attributed to the prophet, suggests an earlier date. Mary Boyce placed the Gathas in the second millennium BCE; Gherardo Gnoli, more cautiously, accepted a range of c. 1500–600 BCE; the question is not closed. Jean Kellens, who has worked the closest on the Gathas in recent decades, treats the linguistic argument for a very early date as the strongest, and his Essais zoroastriens is the place to look for the technical philology. The cluster on Zarathustra as a prophet gives a full account of the scholarly debate.

Zarathustra’s teaching was a prophetic reform of the older Indo-Iranian religion. He proclaimed a single supreme god, Ahura Mazda, the “Wise Lord,” as the creator of the world and the source of all goodness. He opposed the daevas as false gods, and elevated the Amesha Spentas, the “Holy Immortals,” as the emanations or aspects of Ahura Mazda. He taught that the universe is the scene of a cosmic struggle between spenta mainyu (the beneficent spirit) and angra mainyu (the destructive spirit), and that human beings are free to choose between them through their thoughts, words, and deeds. The ethical monotheism of Zoroastrianism, its concept of free will, its eschatology of individual judgment after death, its expectation of a final battle between good and evil followed by the frashokereti (the renovation of the world), and its emphasis on good deeds — especially agricultural work, marriage, and care for the dog — made it, on the doctrinal side, the most distinctive ethical monotheism of pre-Hellenistic western Asia.

The Magi and the priestly class

The Magi, a Median priestly class whose name is preserved in Greek (magoi), Latin (magi), and modern English (“magi,” “magician”), were central to the religious life of the Iranian world. Herodotus, writing in the fifth century BCE, described them as a tribe of the Medes who interpreted dreams, performed sacrifices, and advised the Persian kings. The Achaemenid inscriptions show that the Magi accompanied the royal court and conducted the fire ritual. The cluster on the Magi, the priests of ancient Media gives a full account of the class and its later history, including the development of the word “magi” in Greek and Latin to mean “magician” and the identification of the Magi with the wise men of the Gospel of Matthew.

The Magi were not only a priestly caste. They were specialists in astrology, dream interpretation, and the reading of omens, and their knowledge of the stars was one of the major sources of the Hellenistic astrological tradition. The Sasanian court employed the mobads (priests) and the herbeds (teachers) of the Zoroastrian church as advisers to the shah, and the dastur (senior priest) was often a member of the inner council of the state. The fall of the Sasanian state in the seventh century dispersed the Zoroastrian priesthood across Iran, Central Asia, and the Indian subcontinent, where the Parsi community preserved the priestly tradition in a new diaspora.

Zoroastrianism under the Achaemenids

Zoroastrianism did not become the official state religion of Iran until the Sasanian period, but it was clearly a major religious tradition under the Achaemenids. The Behistun inscription of Darius I, composed in Old Persian, Elamite, and Akkadian, invokes Ahura Mazda as the supreme deity and describes the king’s support for the Zoroastrian ritual. Cyrus the Great is notable for his religious tolerance: the Cyrus Cylinder mentions the gods of Babylon, Sumer, and Akkad without naming Ahura Mazda. Whether the Achaemenid kings were themselves Zoroastrians in the later doctrinal sense is debated; Boyce argued for a strong identification, Kellens has been more cautious. The cluster on Zoroastrianism examines the relationship in detail.

After Alexander and the establishment of the Seleucid and Arsacid states, the Iranian religious tradition entered a long period of adaptation. The Parthian Arsacids were tolerant of Greek religion and culture, and the Hellenistic cities of Mesopotamia, Iran, and Central Asia produced a religious synthesis in which Iranian, Greek, Babylonian, and Jewish elements mingled. It was in this period that the cult of Mithras took its Roman form, and the cult of Anahita, the Iranian goddess of the waters, spread across the Iranian world.

Sasanian Zoroastrianism

The Sasanian Empire (224–651 CE) was, in religious terms, the most thoroughly Zoroastrian state in Iranian history. Ardashir I allied himself with the Zoroastrian priesthood, and his successors, especially Shapur I and Khosrow I Anushirvan, patronised the church, codified the Zoroastrian scriptures, and imposed the Zoroastrian law on the empire. The Sasanian Empire was, in the strict sense, a Zoroastrian state in which the shah and the dastur shared authority.

The Sasanian synthesis combined the older Zoroastrian tradition with the philosophical and scientific inheritance of late antiquity. The Academy of Gondeshapur, founded in the third or fourth century CE (the date is debated; the traditional founding is 271 CE under Shapur I), brought together Greek, Indian, Syriac, and Persian scholars in a programme of translation and original research. Greek philosophical works by Plato, Aristotle, and the Neoplatonists were translated into Pahlavi. Indian astronomical, mathematical, and medical texts were rendered into Middle Persian. The resulting synthesis shaped the theology, ethics, and natural philosophy of the Islamic world.

Mithraism

The cult of Mithras is the single most successful Iranian religious export of the ancient world. The Indo-Iranian god Mithra, originally a deity of contracts, oaths, and the sun, became, in the Iranian tradition, a major yazata and the subject of the longest hymn of the Avesta, the Mihr Yasht. After Alexander’s conquest, the cult spread westward through the Hellenistic kingdoms, and by the first century CE it had become the most popular mystery religion of the Roman army, with sanctuaries from Britannia to Syria and from the Rhine to the Danube.

Roman Mithraism was a mystery religion in which initiates progressed through seven grades corresponding to the seven planets, and participated in a shared ritual meal of bread and water. The central image of the cult, the tauroctony (Mithras slaying a cosmic bull), was a standardised scene carved in virtually every Mithraeum. The relationship between Roman Mithraism and the Iranian cult of Mithra is one of the contested problems in the history of religion. The iconographic parallels with the Christian passion of Christ — the shared ritual meal, the birthdate of December 25 — have been the subject of scholarly debate for centuries. Neither direction of influence is established. The cluster on Mithraism and the cult of Mithras traces the transmission in detail.

Zurvanism

Zurvanism, the doctrine that Zurvan, an abstract deity of infinite time, was the father of both Ahura Mazda and Angra Mainyu, was a major theological school of the late Achaemenid and Sasanian periods. The doctrine is attested in Middle Persian, Armenian, and Greek sources, and was the object of extensive debate among Sasanian and early Islamic scholars. The long-tail page on Zurvanism in Persian religion examines the doctrine in detail.

Zurvanism was, in effect, a philosophical reformulation of Zoroastrianism that responded to the problem of dualism: if Ahura Mazda is good, where did evil come from? The Zurvanite answer was that both good and evil, both Mazda and Angra Mainyu, were the products of a more fundamental principle, infinite time. The doctrine was condemned by the orthodox Zoroastrian church in the Sasanian period, but it remained influential in the philosophical tradition. Traces of it have been detected in Manichaeism, in the early Islamic qadar debates, and in certain schools of medieval Jewish and Christian thought. R. C. Zaehner’s Zurvan: A Zoroastrian Dilemma (1955) remains the classic Western study, though its conclusions have been challenged by later scholars, and the field has moved on.

Manichaeism

Manichaeism, founded by the Sasanian prophet Mani (216–274/277 CE), was the most ambitious religious synthesis between the Buddha and Muhammad. Combining elements of Zoroastrianism, Christianity, and Buddhism in a radical dualist system, Manichaeism spread from the Sasanian Empire across the Roman world, Central Asia, and China, where it survived, in the form of the Chinese Manichaean church, into the Ming dynasty. The Medinet Madi codices in Egypt (the Kephalaia, the Psalms, the Homilies), discovered in the early twentieth century and now mostly in the Chester Beatty Library in Dublin and the Berlin-Brandenburgische Akademie, have transformed the field since their first scholarly editions.

Mani’s claim to be the “Seal of the Prophets,” the culmination of a series of revelations including those of Zoroaster, the Buddha, and Jesus, was a direct challenge to the Zoroastrian priesthood, and Mani was imprisoned and executed by the Sasanian king Bahram I. After his death, the Manichaean church survived as a persecuted minority, and its influence on Augustine of Hippo (a Manichaean before his conversion), on the Bogomils of the Balkans, on the Cathars of southern France, and on the Uyghur state of the eighth to ninth centuries is a striking testimony to the diffusion of Iranian religious ideas across the Old World.

Mazdakism

Mazdakism, a religious movement that emerged in the late Sasanian period, was an egalitarian offshoot of Zoroastrianism that preached the community of property and of wives. The movement is associated with the reign of Kavad I (488–496, 498–531 CE) and was brutally suppressed by Khosrow I Anushirvan, who executed Mazdak and many of his followers. The movement is, however, important for the development of Islamic and Persian social thought, and traces of Mazdakite ideas can be found in the Ismaili, Qarmati, and Sufi traditions of the medieval Islamic world. The details of Mazdak’s teaching are partly obscured by hostile Sasanian and later Islamic sources, and the modern historiography (notably Patricia Crone and Hendrik Kramers) has questioned the more idealistic reconstructions.

Influence on Judaism, Christianity, Islam

The influence of Persian religion on the Abrahamic traditions was substantial. The Jewish diaspora in Mesopotamia had been in contact with Iranian religious ideas since the Achaemenid period, and a number of doctrines that became central to late biblical and rabbinic Judaism — the resurrection of the body, the last judgment, heaven and hell, the figure of Satan as an opponent of God, the role of angels as ministering spirits, and arguably the messianic age — were developed or significantly elaborated during and after the Babylonian Exile. Shaked’s essays in Dualism in Transformation (1994) and Russell’s Zoroastrianism in Armenia (1987) are the standard Western treatments of the Jewish-Iranian religious interface. The synagogue as an institution may have Persian roots, though this is debated.

Christianity emerged in a world dominated by Roman and Iranian political power, and the early Church was in constant contact with Persian religious ideas. The Magi of the Gospel of Matthew are presented in later Christian tradition as Persians, though Matthew calls them only “from the east.” The cult of Mithras and the Christian Eucharist share features that have been the subject of extensive debate. The Sasanian concept of the divine glory (farr) and the Christian doctrine of divine grace have a suggestive parallel. The Sasanian Church of the East, the Nestorian church that flourished under Sasanian protection (in the periods when it was not being persecuted), was the most substantial Christian body in Asia for several centuries.

Islam, the third Abrahamic religion, emerged in the seventh century in a region that had been part of the Sasanian Empire for centuries, and the influence of Persian religious ideas on the Quran and the early Islamic tradition is unmistakable. The Quranic concepts of the last judgment, the bridge (sirat) over hell, the weighing of deeds, the heavenly book, and the throne of God all have close parallels in Zoroastrian eschatology. The Persian tradition of the sacred kingship of the shah was adapted by the Umayyad and Abbasid caliphs in their own self-presentation. The great Persian Sufi tradition, from Bayazid Bastami and Hallaj in the ninth century to Rumi and Hafez in the thirteenth and fourteenth centuries, was a major vehicle of the transmission of Persian religious thought into the wider Islamic world.

Persian philosophy from Gondeshapur to Ibn Sina

The Sasanian Academy of Gondeshapur was the institutional matrix of a long tradition of Persian philosophical and scientific thought. The scholars of Gondeshapur translated Greek philosophical, medical, and scientific works into Pahlavi and Syriac, and the resulting corpus became the basis of the Islamic scientific tradition when the Academy was incorporated into the Abbasid caliphate in the eighth century. Dimitri Gutas’ Greek Thought, Arabic Culture (1998) is the standard modern treatment of the transmission, and it is more cautious than the older literature about the directness of the Sasanian-to-Abbasid inheritance.

The major figures of medieval Persian philosophy — al-Kindi, al-Farabi, Ibn Sina (Avicenna), al-Biruni, Omar Khayyam, Nasir al-Din al-Tusi — worked within a tradition that was, in its origins, the synthesis of Greek, Indian, and Iranian thought achieved in the Sasanian period. Ibn Sina, whose Kitab al-Shifa and Qanun al-Tibb were the standard philosophical and medical texts of the medieval Latin West, was a Tajik Persian from Bukhara. Al-Biruni, the great polymath of the Ghaznavid court, was a Khwarezmian Persian who mastered Sanskrit, Greek, Arabic, and Persian. Nasir al-Din al-Tusi, the thirteenth-century philosopher and astronomer, was a Twelver Shia from Tus. The Persian tradition is, in practical terms, the bridge between the Greek and the modern worlds: the Greek works survived into the medieval period through Arabic translations that were then transmitted into Latin, and the Persian-speaking scholars who worked in the chain — al-Farabi, Ibn Sina, al-Biruni, Khayyam, Tusi — gave the Latin West its Aristotle, its Ptolemy, and its Euclid.

The later tradition included Mulla Sadra (c. 1571–1636), the Safavid philosopher whose Transcendent Theosophy (al-Hikma al-Mutaʿaliya) synthesised Avicennan philosophy, Sufi metaphysics, and Twelver Shia theology into the most influential school of Islamic philosophy in the early modern period. The school continues in the seminaries of Qom and Najaf, and the principal modern edition of Mulla Sadra’s al-Asfar is the Iranian one of 1378–1383 Sh.

Sacred literature and the lost Avesta

The sacred literature of the Zoroastrian tradition is collected in the Avesta, the canon of texts composed in Avestan, Old Persian, and Middle Persian. The oldest stratum, the Gathas, is composed in a dialect of Old Avestan and attributed to Zarathustra himself. The Yasna, the liturgical collection, includes the Gathas and a number of other ritual texts. The Visperad is a set of extensions to the Yasna used in the Gahambars, the seasonal festivals. The Vendidad is a code of ritual law, hygiene, and legal procedure. The Yashts are a collection of twenty-one hymns in praise of the yazatas, the divine beings worthy of worship. The long-tail page on what the Yashts are gives a full account, including the Mihr Yasht in praise of Mithra, the Aban Yasht in praise of the waters, the Ardvisur Yasht in praise of the river goddess Anahita, and the Bahman Yasht, the apocalyptic hymn.

The Avesta as we have it is only a fraction of the original. The Sasanian Avesta, organised under the direction of the Zoroastrian high priest Adurbad Mahraspandan in the late Sasanian period (c. fourth century CE, under Shapur II or his successors), was a much larger canon of twenty-one nasks, or volumes, of which only the liturgical texts and a single nask of the Yashts survive in the Avestan language. The rest of the Sasanian Avesta, the Zand (the Middle Persian translation and commentary), is lost in the Avestan original. The major Sasanian Pahlavi texts — the Bundahishn, the Denkard, the Arda Viraf Namak, the Zand-i Wahman Yasn — preserve the substance of the lost material. The Denkard, the “Acts of the Religion,” is a ninth-century encyclopedia of Zoroastrian theology, philosophy, and law and the single most important Pahlavi text outside the Bundahishn.

What we don’t know

A word on the limits. The date of Zarathustra is the most famous unknown; the linguistic argument is suggestive but not decisive, and the archaeological record has not yet produced a smoking gun. The relationship between Roman Mithraism and the Iranian cult of Mithra is, in my view, an unsolvable problem given the present evidence. The textual transmission of the Sasanian Avesta is so lossy that the original canon can only be reconstructed in outline. The origins of the Manichaean psalms, the routes of the Buddhist-Iranian artistic exchange in Bactria, the actual practice of the Sasanian church at the village level — these are all dark. The field has, in the last forty years, gone from confident reconstruction to honest puzzlement, and that is, on balance, a healthy development.

The Persian religious tradition is the largest single body of inherited practice and thought that the modern Iranian world, the Parsi diaspora, and the wider Persianate cultural sphere have to draw on. The treatment of it in the modern disciplines of religious studies, Iranian studies, and comparative philosophy has been rigorous and increasingly honest about the limits. The next generation of scholarship will be, if anything, more cautious still. The field is in good hands.