The great work of Zoroaster, or rather Zarathustra, the Mede, who reformed the Magian religion. It is the Avesta or “Living Word,” written in the Zend language (B.C. 490). It now contains the Yacna, the Vispered, the Vendidad, and the Khordah-Avesta.
“The sacred writings of the Parsees have usually been called Zend-Avesta by Europeans; but this is, without doubt, an inversion
of the proper order of the words, as the Pahlavi books always style
them `Avisták-va-Zand' (text and commentary).” —
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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