(I) The Gāthās of Zoroaster (Zarathushtra), the prophet whose see must have been somewhere in Afghanistan, and whom the Zoroastrian tradition dates in the first half of the 6th century B.C. They are composed in an Avestan dialect characterized by features of grammar and phonology more archaic than the dialect of most of the other Avestan texts, those mentioned under (3) and (4). The latter dialect is therefore called “Younger Avestan”, somewhat misleadingly because, in the absence of proof that it evolved from the Gathic dialect, it may well be as old as the Gāthās. However, the surviving texts themselves which are couched in “Younger Avestan” language have been dubbed the “Younger Avesta” with some justification, because their authors dilute Zoroaster's tenets with pre-Gathic beliefs rejected by him. The composition, as against the language, of the Younger Avesta, is therefore indeed “younger” than the Gāthās, whose metrical versification, moreover, resembles more that of the Vedas than that of the Younger Avesta.