The creed and ritual of the Brahmans, or that social, political, and religious organisation which developed among the Aryans in the valley of the Ganges under the influence of the Brahmans. According to the religious conception of this class, Brahma, or the universal spirit, takes form or incarnates himself successively as Brahma, Vishnu, and Siva, which triple incarnation constitutes a trimurti or trinity. In this way Brahma, the first incarnation of the universal spirit, had four sons, from whom issued the four castes of India—Brahmans, Kshatriyas, Vaisyas, and Sudras—all the rest being outcasts or pariahs. See Caste .