Zoroaster (Properly Zarathustra), the founder of the ancient Persian religion. Respecting his career, his period, and his history as reformer of the earlier religion of his people, we have scarcely any trustworthy information. He was by birth a Bactrian; and the native tradition, ancient and modern, declares him to have been the son of Pourushaspa, and to have lived under a king Vistaspa (Gushtasp, Hystaspes), who accepted and favored the general adoption of his doctrines. This king was at one time regarded as identical with the father of the first Darius, and Zoroaster was accordingly assigned to the 6th century B. C.; but this opinion is now given up. The Persian traditions make Vistaspa the last of the line of Kaianian princes, ruling in Bactria; and as the Assyrian conquest of Bactria is said to have taken place 1,200 years B. C, it has been concluded with some plausibility that Zoroaster's life must have preceded that event, perhaps by no long interval, especially as the Zoroastrian scriptures betray no acquaintance with any of the nations dwelling in or near the western parts of Iran, as the Medes, the Persians, the Assyrians, etc.

In the ZendAvesta he appears as a being of supernatural endowments, and as receiving from the supreme divinity by personal interview, by inquiry and reply, the truths which he is to communicate to men. The earliest portions of the Avestan text, the Gathas, may perhaps go back in part to his own time. (See Parsees, and Zexd-Avesta).