Quick questions on Persian religion under Darius and Xerxes: HSC Ancient History

The Achaemenid empire was religiously diverse by necessity. At its Persian core, the kings invoked Ahura Mazda as the sole source of royal legitimacy. In Babylon, the ancient cult of Bel Marduk continued largely undisturbed, its priesthood and temple estates intact. In Judah, the god Yahweh's temple in Jerusalem was rebuilt with royal permission and, eventually, royal confirmation.

Whether Darius and Xerxes practised the religion founded by the prophet Zoroaster (Zarathustra) is a genuine, unresolved scholarly debate, and it turns on dating. The Greek chronographer Xanthus of Lydia, preserved by the later writer Diogenes Laertius, placed Zoroaster "6,000 years" before Xerxes's crossing into Greece (480 BC), a legendary, symbolic figure rather than a historical date; other classical writers gave equally fantastical, wildly different figures. Modern scholars instead date Zoroaster on linguistic grounds: the Gathas, hymns attributed to Zoroaster within the later Avesta, are composed in an archaic form of Avestan close to the language of the Rig Veda, which most specialists take to place their composition somewhere in the later second millennium BC, centuries before the Achaemenid dynasty was founded by Cyrus around 550 BC. The exact date remains contested and imprecise.

The inscription known to scholars as XPh, found at Persepolis, is Xerxes's own account of suppressing a form of worship. In it, Xerxes states that among the countries he ruled there was one where the daivas, a class of divine beings that Zoroastrian tradition rejects as false gods or demons, were worshipped. He records that he destroyed that sanctuary of the daivas, proclaimed "the daiva shall not be worshipped," and instituted the worship of Ahura Mazda there instead. The word itself is revealing: "daiva" is the Iranian cognate of the Vedic Sanskrit "deva" (a god), so the same ancient word split into "demon" in one branch of Indo-Iranian religion and "god" in the other, a linguistic fossil of a real theological realignment.

The central evidence for Achaemenid religious tolerance predates Darius and Xerxes but sets the template they inherited and, in the case of Jerusalem, personally continued. After Cyrus took Babylon in 539 BC, the Cyrus Cylinder, a clay cylinder inscribed in Akkadian in the conventional genre of a Mesopotamian royal building and restoration inscription, records him restoring the cult statues of Marduk and other Babylonian gods to their shrines, reversing what the text presents as the impious policies of his predecessor Nabonidus, and framing Marduk himself as having chosen Cyrus as king. Historians such as Amelie Kuhrt argue firmly against the popular modern framing of the Cylinder as a proto "charter of human rights": it follows an established genre of self-legitimising royal rhetoric used by Assyrian and Babylonian kings for centuries before Cyrus, so its claims of piety are conventional, not disinterested.