The process thus deducible from the main conditions is found actually happening in more than one of the ancient cultures, as their history is now sketched. In the Rig-Veda, which if not the oldest is the least altered of the Eastern Sacred Books, the main line of change is obvious enough. It remains so far matter of conjecture to what extent the early Vedic cults contain matter adopted from non-Aryan Asiatic peoples; but no other hypothesis seems to account for the special development of the cult of Agni in India as compared with the content and development of the other early Aryan systems, in which, though there are developments of fire worship, the God Agni does not appear. [125] The specially priestly character of the Agni worship, and the precedence it takes in the Vedas over the solar cult of Mitra, which among the kindred Aryans of Iran receives in turn a special development, suggest some such grafting, though the relations between Aryans and the Hindu aborigines, as indicated in the Veda, seem to exclude the possibility of their adopting the fire-cult from the conquered inhabitants, [126] who, besides, are often spoken of in the Vedas as "non-sacrificers," [127] and at times as "without Gods." [128] But this is sometimes asserted even of hostile Aryans. [129] In any case the carrying on of the two main cults of Agni and Indra side by side points to an original and marked heterogeneity of racial elements; while the varying combination with them of the worship of other deities, the old Aryan Varuna, the three forms of the Sun-God Aditya, the Goddess Aditi and the eight Adityas, the solar Mitra, Vishnu, Rudra, and the Maruts, imply the adaptation of further varieties of hereditary creed. The outcome is a sufficiently chaotic medley, in which the attributes and status of the various Gods are reducible to no code, [130] the same feats being assigned to several, and the attributes of all claimed for almost any one. Here, then, were the conditions provocative of doubt among the critical; and while it is only in the later books of the Rig-Veda that such doubt finds priestly expression, it must be inferred that it was current in some degree among laymen before the hymn-makers avowed that they shared it. The God Soma, the personification of wine, identified with the Moon-God Chandra, [131] "hurls the irreligious into the abyss." [132] This may mean that his cult, like that of his congener Dionysos in Greece, was at first forcibly resisted, and forcibly triumphed. At an earlier period doubt is directed against the most popular God, Indra, perhaps on behalf of a rival cult. [133] Later it seems to take the shape of a half-skeptical, half-mystical questioning as to which, if any, God is real.