But we have seen that Magianism and Zoroastrianism were originally entirely distinct, and that the Zendavesta in all its earlier portions belongs wholly to the latter system.

Nothing therefore is proved concerning the Zend dialect by establishing a connection between the Medes and Magism, which was a corrupting influence thrown in upon Zoroastrianism long after the composition of the great bulk of the sacred writings.
These writings themselves sufficiently indicate the place of their composition.

It was not Media, but Bactria, or at any rate the north-eastern Iranic country, between the Bolor range and the Caspian.
This conclusion, which follows from a consideration of the various geographical notices contained in the Zend books, had been accepted of late years by all the more profound Zend scholars.

Originated by Rhode, it has also in its favor the names of Burnouf, Lassen, Westergaard, and Haug.

If then the Zend is to be regarded as really a local dialect, the idiom of a particular branch of the Iranic people, there is far more reason for considering it to be the ancient speech of Bactria than of any other Arian country.