SANSKRIT AND INDO-EUROPEAN 3 The earliest document of the linguistic history of Indo- ATyan is the Rgveda, which, by rough guess-work, is placed in the region of 1000 b,c. The language we find there is the source from which all later developments in India have arisen. But this language itself had evolved out of a yet earlier form of speech, by precisely the same kind of slow change and altera- tion which caused it to evolve later into something else. This earlier evolution is unrecorded by any direct documentation, but it can be reconstructed in considerable detail by means of comparison with related languages. By this method two stages in the prehistory of the language can be established : (i) By comparison of early Indo-Aryan with the very closely related Iranian, it is possible to form a fairly accurate idea of the original Indo-Iranian or Aryan language from which both have evolved. (2) By comparing Indo-Aryan and Iranian with the other Indo-European languages (enumerated below) it is pos- sible also to go beyond this, and to reconstruct in general out- line the characteristics of the original language from which all these are derived. Since Iranian in view of its very close relationship with Indo- Aryan is of the first importance for the study of Indo-Aryan philology, a short account of its distribution and documentation is desirable. The migration of the Indo-Aryans to India brought about, or perhaps was the final stage of, the separation of the primitive Aryan community into two distinct divisions which henceforth evolved separately in linguistic as in other respects. The Iranians left behind in the region of the Oxus valley 1 proceeded to expand rapidly in various directions, occupying not only the Iranian plateau which remained their centre of gravity, but also large tracts of Central Asia, extending on the one hand to the confines of China and on the other hand to the plains of South Russia. From an early period Iranian showed a much stronger tendency to differentiation into separate dialects which soon became independent languages than was the case with Indo-Aryan, which for geographical and other reasons maintained a comparative unity over most of North India for a very long period. For the old period Iranian is represented by documents in Avestan and Old Persian, and it is these texts which are of 1 A recollection of Chorasmia as their original home is preserved in the traditions of the ancient Iranians.
