From what has been explained above, it is evident that the subject might present itself in a different light. It is well known that the people of India represents, both in its language and in its mythology, the oldest stage of the Aryan mind attainable by us, and after it follows the people of Iran. The ancient literature of these two nations, but that of the Indians more than that of the Persians, stands much nearer in its ideas to the nomadic life than any other documents of the Aryan mind which have been preserved to us. It is then no wonder if (it being a rule in all physical as well as intellectual development, that at a later stage of progress residua of a previous one remain behind unnoticed) these nations, which at the time of their oldest known intellectual productions were not far removed from nomadism, exhibit more traces of nomadism than others, even if they be found to have then fully passed out of the nomadic stage. We have already referred to this in treating of the nomadic elements in chronology, and now return again to the same point. In some things the Iranians preserved the traditions of nomadism more firmly and persistently than the Indians, who generally stood nearer to the original forms. This is to be explained from the fact that in Persia nomadism itself lived longer as an actual stage of civilisation, and was more fostered, than in India; for indeed it even now maintains its position there. For just as in the time of Herodotus (I. 125) the Persians were partly migratory nomads (νομάδες), partly settled agriculturists (ἀροτῆρες), so now a proportion, varying from a quarter to a half, of the population of modern Persia still leads a nomadic life.[184] One characteristic of the nomadic period is a social and political division into tribes, which in many civilised nations is retained into the time of fixed dwellings as a residuum of nomadism. Without pausing over the Thracians, who according to the account of Herodotus,[185] found it impossible to throw off all reference to tribe-differences and bring their power to bear through national unity, we will refer to the Ionians as an example, whose divisions into φρατρίαι, γένη, and γεννῆται, have been accurately traced.[186] Now among the Indians we find no trace of tribal divisions worth mentioning, but very soon come across the Caste—an hereditary division according to modes of occupation, which cannot be formed at any earlier stage than that of fixed dwellings, since this gave the first impulse to the practice of arts and trades, which is not conceivable at the nomadic stage. Among the Iranians, on the other hand, the tribal division maintained itself for a long time parallel with that according to occupation, which was better suited to the time of transition to a fixed life.[187] Even on the Caste system of the Parsees the tribal division still exerts a definite influence. The sacerdotal caste is a distinct