INTRODUCTION
THE earliest record of Indian mythology is contained in the Ṛgveda, or "Hymn Veda," a series of ten books of hymns celebrating the chief Vedic gods. The exact motives of the collection are uncertain, but it is clear that in large measure the hymns represent those used in the Soma sacrifice, which formed a most important part of the worship of the gods in the ritual of the subsequent period. It is now recognized that the religion and mythology contained in this collection are not primitive in character and that they represent the result of a long period of development of sacred poetry. Thus it is that the gods who form the subject of this poetry often appear obscure in character, though in the great majority of cases it is clear that the myths related of them refer to physical happenings. The date of the Ṛgveda is much disputed and admits of no definite determination; it may be doubted whether the oldest poetry contained in it is much earlier than 1200 B.C., but it is not probable that it was composed later than 800 B.C., even in its most recent portions.
Both in its mythology and in its composition the Ṛgveda is clearly older than the other three Vedas, the Sāmaveda, the Yajurveda, and the Atharvaveda—the "Chant Veda," the "Formula Veda," and the "Veda of the Atharvan Priests"—and, in point of date, these three stand much on a level with the Brāhmaṇas, or explanatory prose texts which are attached to or form part of them. In them are to be found many speculations of a more advanced kind than those of the Ṛgveda, yet at the same time the Atharvaveda contains a mass of popular religion which has been taken up and worked over by the same priestly classes to whose activity the other texts are due. It