Zoroastrianism (…) originated some four millennia ago. - Prods Oktor Skjaervo

A very few geographical names appear to be inherited from Indo-Iranian times. For instance, OPers. Haraiva-, Av. (acc.) HarOiium, and OPers. HarauvatI, Av. HaraxvaitI-, both of which in historical times are located in the area of southern Afghanistan (Herat and Kandahar), correspond to the two Vedic rivers Sarayu and SarasvatI. These correspondences are interesting, but tell us nothing about the early geography of the Indo-Iranian tribes.

“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”.

Since the classical Greeks already, it has been common to date Zarathuštra to the 6th century BC, hardly a few generations before the Persian wars. In popular literature, this date is still given, but scholars have now settled for an earlier date: “The archaism of the Gāthās would incline us to situate Zarathuštra in the very beginning of the first millennium BCE, if not even earlier.” (Varenne 2006) But how much earlier? According to leading scholar SkjaervØ, “Zoroastrianism (…) originated some four millennia ago”.