The earliest reference to Ahûrá Mazdá in ancient records appears to be in an Assyrian text, probably of the 8th century B.C.E, in which Assara Mazaš, is named in a list of Indo European gods.
The list in which the name Assara Mazaš appears, contains a number of old Aryan divinities, honored in outlying borders of the Assyrian Empire, on the peripheries of the towering Zagros mountains of Western Iran, the ancient homeland of the Medes. Professor Hommel was of the opinion that this Assara Mazaš, is Ahûrá Mazdá the chief god power of Zoroastrianism.
Interestingly, the order of Assara Mazaš corresponds to Ahûrá Mazdá of the Younger Avesta, but in the poetic gathas, or the oldest part of the Avesta, the order is reversed, and appears as Mazdá, Ahûrá.
This strongly suggests that the Zoroastrianism of the Younger Avestan period was firmly established in Western Iran before 8th century BCE, and that the Zoroastrian divinities of the Aryan Medes were well known to the Assyrians at that point in history.
The desire to push the age of Zarathustra to 600 BCE goes back directly to the VERY MISTAKEN identity of Zoroastrianism with the idea of Monotheism. Monotheism without a shadow of doubt goes back to Pharaoh Akhenaten and to ancient Judaism.
To identify Zoroastrianism with biblical monotheism is simply put wishful thinking. Zoroastrianism defines itself as Mazd-yasná “zeal, passion, fervor for Mazdá.” Yasná is a cognate of Greek word zelós and Mazdá is the supreme Ahûrá, chief god of “imagination, inspiring creativity, and mind power.”
While Zeus the chief of the Greek Gods, is a cognate with the Vedic Dyaus, which stems from the Indo-European root *dyeu-, referring to “the bright sky of the day and celestial gods,” the supremacy of Mazdá (Cognate with Greek Muses) derives from the journey and evolution of mind and consciousness.
Mazdá or Ma(n)zdá (*mens-dheh-) derives from the Indo European root *mens of the stem ménos “mind-force, will power, spirit, determination, resolve” and the verb dheh “to set, establish, do, create.” (Courtesy of Didier Calin)
Prophet Zarathustra saw Godhood NOT in superhuman celestials, but in the odyssey of consciousness, the power of spirit/mind to discover and create.”
Ahûrás in Zarathustra’s doctrine are “master artisans of ašá/arthá or the innovative cosmic order.” All the divine entities in the Zoroastrian sacred lore are animated by the creative imagination and evolving mind power that is embodied in Mazdá, who is the essence/wondrous substance of all the Immortal Gods.
There is nothing static or final about any aspects of Godhood in the poetic gathas and Zoroastrianism. Brilliant Immortals each embody the eternal quest for excellence, discovery, and new horizons of mind/consciousness.
Mazdá is the god of ménos “determination, fighting spirit, discovery, will and mind power,” the supreme ahûrá, and the well-spring of all the Immortal Gods, and evolving god-men and women!
I like to conclude by the following verse from the poetic gathas, Yasna 43.10, 2nd rhymed verse line:
ýé ãn.ménî mazdáv srávî ahûrö
In ménos “fighting spirit, discovery, will and mind power” Mazdá the Mindful Lord, is heard srávî in imperishable glory.