On comparing with one another the two most ancient periods of development of the Iranian mind, in language as well as in literature,—that primitive one, whose witness is the Avesta, with the period of renaissance under Sasanian rule,— we find at once this striking difference, that the former is purely national and Iranian, almost wholly free from any foreign influence, whilst the latter, as it appears in the Pahlavi translations and the inscriptions of the Sasanian kings, is overwhelmed by foreign, Semitic, or more accurately speaking, Aramæan elements. The difficulties in explaining the pure Persian substratum of the language of this latter period, for even here not every problem has yet been solved, are by no means to be compared with those offered by the Semitic forms and words, which appear to the Indo-german linguist utterly unknown, to the Semitic scholar more than strange. Though a great quantity of highly valuable material has already been collected and digested by European scholars, still I do not think it sufficient to enable us to decide in a satisfactory manner the following questions:—During what time did that close intercourse between the Iranian and Semitic races take place, the existence of which we are compelled to assume as the source of the Semitic portion of the Pahlavi language? Of what kind was this intercourse? And with which of the Aramæan nations in particular? The same questions demand an answer, in order to explain the numerous Iranian words which occur in the literature of the Babylonian Jews, in Syriac, in the Koran, and the most ancient Arabic poems.