Written by A standalone piece
For five centuries, the finest minds of Greece and Rome looked back toward Zoroaster and saw the same thing: a figure standing at the very dawn of the world, ancient almost beyond reckoning. And these were not credulous men. Xanthus of Lydia, the first Greek ever to write his name, placed him thousands of years before Xerxes. Eudoxus — among the greatest mathematicians antiquity produced — and Aristotle himself set him six thousand years before Plato. Hermippus, who claimed to have read the Magian books, and Plutarch, the master biographer, reckoned five thousand years before the fall of Troy. Pliny, charting the origins of human knowledge, placed Moses “many thousand years after Zoroaster.” And Diogenes Laertius gathered their voices into one.
They quarreled over the number. They never once quarreled over the verdict. Whether the count ran to six thousand years or five, every authority who weighed the question reached for the same superlative — older than Moses, older than any sage of their own world, a teacher already immemorial when history itself was young. Search the entire classical record, and you will not find a single voice that called him recent.
This was the judgment of the ancient world, rendered with one accord across five hundred years and a dozen hands: that Zarathustra was old when the world was young. What follows is the evidence behind that verdict — and the reason it turns out to be not merely an ancient opinion, but very likely the truth.
The chronographers
The classical figures for Zoroaster’s age, gathered, form a remarkable chorus. Xanthus of Lydia, writing in the fifth century BCE and the earliest Greek to name him, set him six thousand years before Xerxes’ crossing into Greece.[^1] Eudoxus of Cnidus and Aristotle — cited together by later authors — placed him six thousand years before the death of Plato.[^2] Hermippus of Smyrna, who professed to have studied the Zoroastrian books themselves, and Plutarch, in his account of Persian religion, gave five thousand years before the Trojan War.[^3] Pliny the Elder gathered these reckonings into his survey of the origins of knowledge, and added the pointed note that the Jewish learning he traced to Moses arose “many thousand years after Zoroaster.”[^4] Diogenes Laertius, opening his great history of philosophy, collected the whole tradition.[^5]
A word of honesty makes this stronger, not weaker. These figures — six thousand years, five thousand years — are not calendar measurements; they are schematic numbers, drawn from a cosmological sense of vast world-ages, and they should not be cited as though anyone had counted the years. But notice what the variation reveals: the authorities disagreed on the figure precisely because none of them was reading a date off a record. What they agreed on, with one voice and no exception, was the verdict — that Zoroaster belonged to a remote and fabulous antiquity. The disagreement over the number is itself the proof that the consensus on his ancientness was independent and genuine, not copied from a single source. They arrived at the same conviction by different roads.
The wider testimony
Beyond the chronographers, the whole weight of classical reference treats Zoroaster as the ancient archetype. Herodotus, in the fifth century BCE, described the Magi — his priesthood — as a fixture of the Persian and Median world.[^6] Plato named “Zoroaster son of Oromazes” as the fountainhead of the Magian lore taught to the Persian princes.[^7] Theopompus, in the fourth century BCE, recorded the actual Zoroastrian doctrine — the two spirits, the cosmic ages, the final renovation — as the teaching of an established and venerable tradition.[^8] Diodorus Siculus ranked him among the great lawgivers of remote times.[^9] Strabo described his priesthood and its rites as an ancient institution of the Persian world.[^10] Not one of these treated Zoroaster as a recent teacher; every one assumed his deep antiquity as a settled fact of the world they knew.
And the regard outlived antiquity itself. The Neoplatonists revered a body of oracles they attributed to Zoroaster as primordial wisdom; the Renaissance Platonists — Gemistus Pletho, Marsilio Ficino, Pico della Mirandola — placed him at the very head of the prisca theologia, the most ancient theology from which all later wisdom was thought to descend.[^11] For more than two thousand years, the West’s verdict on Zoroaster’s antiquity never wavered.
The Iranian reckoning
The tradition’s own reckoning agrees on the substance, if not on the fabulous Greek figures. The Zoroastrian Religious Era, used by the Zoroastrian assemblies, places Zarathustra’s calling at 1738 BCE; the Middle Persian Bundahishn, by its reckoning of “258 years before Alexander,” brings him to about 589 BCE.[^12] Iranian memory, like Greek and Roman testimony, located him deep in the past.
The anchor: his own words
Here is what raises the verdict of the ancient world above mere ancient opinion. Zoroaster left his own hymns, the Gathas, and they can be dated by a measure the ancients did not possess: language. The Gathas are composed in Old Avestan, a tongue so archaic that it is a near-twin of the oldest layer of Rigvedic Sanskrit, and they depict a world that is pre-urban and pastoral — herders and cattle, tribal raids, no cities and no empire.[^13] Language this old and a society this early place Zarathustra, on the reckoning of modern linguists, in the second millennium BCE — roughly 1500–1000 BCE, or earlier.[^14]
This is the quiet vindication of the ancient verdict. The Greeks and Romans had no way to read the age of the Gathas; they reached their conviction of Zoroaster’s vast antiquity by reputation and tradition alone. And yet, when the one tool they lacked — historical linguistics — is finally applied, it lands in the same territory: deep, second-millennium antiquity. The ancient world believed he was immensely old; the evidence of his own archaic words shows that, in substance, it was right.
The verdict, and the proof
So the case stands in two layers, and they reinforce each other. The classical world was virtually unanimous, across five centuries and every kind of authority — historian, philosopher, naturalist, biographer — that Zoroaster was a figure of remote antiquity, older than Moses and older than any sage of the West; that is genuine, citable testimony to his perceived age, and the schematic figures only confirm how independent and unforced the consensus was. And beneath that testimony lies the harder evidence: the archaic language of his own Gathas, which places him in the second millennium BCE on grounds the ancients never knew.
The opinion and the evidence converge. Zarathustra was reckoned ancient by everyone who looked back at him from the classical world — and the language of his own hymns says they were right to. He was, as nearly as the record allows us to say, old when the world was young.
Notes
[^1]: On Xanthus of Lydia as the earliest Greek to name Zoroaster and to give a figure of vast antiquity, see Diogenes Laertius, Lives of the Eminent Philosophers, Prologue 1.2, and the discussion in Albert de Jong, Traditions of the Magi (Leiden: Brill, 1997).
[^2]: On Eudoxus of Cnidus and Aristotle placing Zoroaster six thousand years before Plato, see Diogenes Laertius, Lives, Prologue 1.8, and Pliny, Natural History 30.3.
[^3]: On Hermippus of Smyrna and Plutarch giving five thousand years before the Trojan War, see Pliny, Natural History 30.4, and Plutarch, On Isis and Osiris 46–47 (369d–e).
[^4]: On Pliny gathering these reckonings and placing the Mosaic/Jewish learning “many thousand years after Zoroaster,” see Pliny, Natural History 30.2–4, 30.11. (Pliny himself regarded “magic” as fraudulent; the chronological priority of Zoroaster over Moses is nonetheless what he states.)
[^5]: Diogenes Laertius, Lives of the Eminent Philosophers, Prologue 1.1–9.
[^6]: Herodotus, Histories 1.101, 1.131–132.
[^7]: Plato, Alcibiades I 122a.
[^8]: On Theopompus recording the Zoroastrian dualism and the renovation, see Theopompus, FGrHist 115 F64–65, preserved via Plutarch, On Isis and Osiris 47 (370b–c).
[^9]: Diodorus Siculus, Library of History 1.94.
[^10]: Strabo, Geography 15.3.13–15.
[^11]: On the Neoplatonist Chaldean Oracles attributed to Zoroaster and the Renaissance placement of him at the head of the prisca theologia (Pletho, Ficino, Pico della Mirandola), see the scholarship on late-antique and Renaissance Platonism; and de Jong, Traditions of the Magi, on the Greek reception.
[^12]: On the Zoroastrian Religious Era date of 1738 BCE and the Bundahishn‘s reckoning of c. 589 BCE, see the Zoroastrian liturgical chronology and the Bundahishn.
[^13]: On the archaic Old Avestan of the Gathas (a near-twin of the oldest Rigvedic Sanskrit) and their pre-urban pastoral world, see Mary Boyce, A History of Zoroastrianism, vol. 1 (Leiden: Brill, 1975), and Helmut Humbach et al., The Gāthās of Zarathushtra (Heidelberg: Winter, 1991).
[^14]: On the second-millennium linguistic dating of Zarathustra (c. 1500–1000 BCE or earlier), see Boyce, A History of Zoroastrianism, vol. 1; cf. the Encyclopædia Britannica entry “Zarathushtra” (“born 2nd millennium BCE”).