Avesta

"“Not only in grammatical structure and vocabulary, but also in literary form, in certain metres like the TriSTubh and in a way GAyatrI, there is resemblance between the Avesta and the Rgveda. The fact is usually mentioned in good manuals. But there is a peculiarity about these points of resemblance which is not so commonly known: It is the eighth MaNDala which bears the most striking similarity to the Avesta. There and there only (and of course partly in the related first MaNDala) do some common words like uSTra and the strophic structure called pragAtha occur. … Further research in this direction is sure to be fruitful.”"

"“H. Oldenberg showed that in spite of the genetic closeness of religious beliefs, the Vedas and Avesta differ considerably, and that in the Avesta many of the heroes play opposite roles to their counterparts in the Veda.” (p.183)"

"“Two Young Avestan texts contain lists of countries known to their authors, YaSt 10 and VidEvdAd, Chapter 1. The two lists differ considerably in terms of composition and are therefore most probably independent of one another. Both lists contain only countries in northeastern Iran.” ...[All these places are] “located to the east of the Caspian Ocean, with the possible exception of Raga”."

"[the attempt to transpose the geography of the Avesta from Afghanistan to western Iran] “was doubtless due to different attempts made by the most powerful religious centres of western Iran and the influential order of the Magi to appropriate the traditions of Zoroastrianism that had flourished in the eastern territories of the plateau in far-off times. Without a doubt, the identification of RaYa with AdurbAdagAn, more or less parallel with its identification with Ray, should be fitted into the vaster picture of the late location of Airyana VaEjah in ADarbAyjAn.” ..."

"“It must be emphasised that the process of polarisation of relations between the Ahuras and the DaEvas is already complete in the GAthAs, whereas, in the Rigveda, the reverse process of polarisation between the Devas and the Asuras, which does not begin before the later parts of the Rigveda, develops as it were before our very eyes, and is not completed until the later Vedic period. Thus, it is not at all likely that the origins of the polarisation are to be sought in the prehistorical, the Proto-Aryan period. More likely, ZarathuStra’s reform was the result of interdependent developments, when Irano-Indian contacts still persisted at the dawn of history. With their Ahura-DaEva ideology, the Mazdayasnians, guided by their prophet, deliberately dissociated themselves from the Deva-Asura concept which was being developed, or had been developed, in India, and probably also in the adjacent Iranian-speaking countries… All this suggests a synchrony between the later Vedic period and ZarathuStra’s reform in Iran.”"