It becomes necessary, therefore, to examine this theory, in order to justify our abstention from an inquiry on which, if the theory were sound, we should be now called upon to enter.
The notion that the Zend language was the idiom of ancient Media originated with Anquetil du Perron.

He looked on Zoroaster as a native of Azerbijan, contemporary with Darius Hystaspis.

His opinion was embraced by Kleuker, Herder, and Eask; and again, with certain modifications, by Tychsen and Heeren.

These latter writers even gave a more completely Median character to the Zendavesta, by regarding it as composed in Media Magna, during the reign of the great Cyaxares.

The main foundation of these views was the identification of Zoroastrianism with the Magian fire-worship, which was really ancient in Azerbijan, and flourished in Media under the great Median monarch.