The Egyptian sun god Ra similarly rose from the primordial waters as the sun-egg. Ptah came from the egg which, according to one myth, was laid by the chaos goose, and to another issued from the mouth of Khnumu.[149] This conception may have had origin in the story of the giant of the folk tales who concealed his soul in the egg, in the tree, and in various animal forms. There are references in Indian literature to Brahma's tree, and Brahma is identified with Purusha, who became in turn a cow, a goat, a horse, &c., to produce living creatures. [149] See _Egyptian Myth and Legend_. In Manu's account of Creation we meet for the first time with the Maha-rishis or Deva-rishis, the Celestial priest poets. These are the mind-born sons of Brahma, who came into existence before the gods and the demons. Indeed, they are credited with some acts of creation. The seven or fourteen Manus were also created at the beginning. Originally there was but a single Manu, “the father of men”. The inclusion of the Rishis and the Manus among the deities is a late development of orthodox Brahmanism. They appear to represent the Fathers (Pitris) who were adored by ancestor worshippers. The tribal patriarch Bhrigu, for instance, was a Celestial Rishi. It must be borne in mind that more than one current of thought was operating during the course of the centuries, and over a wide area, in shaping the complex religion which culminated in modern Hinduism. The history of Hinduism is the history of a continual struggle between the devotees of folk religion and the expounders of the Forest Books produced by the speculative sages who, in their quest for Truth, used primitive myths to illustrate profound doctrinal teachings. By the common people these myths were given literal interpretation. Among the priests there were also “schools of thought”. One class of Brahmans, it has been alleged, was concerned chiefly regarding ritual, the mercenary results of their teachings, and the achievement of political power: men of this type appear to have been too ready to effect compromises by making concession to popular opinion. Just as the _Atharva-veda_ came into existence as a book after the _Rigveda_ had been compiled, so did many traditional beliefs of animistic character receive recognition by Brahmanic “schools” after the period of the early _Upanishads_. It may be, however, that we should also recognize in these “innovations” the influence of races which imported their own modes of thought, or of Aryan tribes that had been in contact for long periods with other civilizations known and unknown.