Historical Vedic religion the central ideas and theosophy in the Vedas, and synergistically integrated new ideas. Of the major traditions that emerged from Brahmanism are the six "darshanas", particular the Vedanta, Samkhya and Yoga schools of Hinduism. Vedic religion was followed by Upanishads which gradually evolved into Vedanta, which is regarded by some as the primary institution of Hinduism. Vedanta considers itself "the purpose or goal [end] of the Vedas." There are some conservative schools which continue portions of the historical Vedic religion largely unchanged (see Śrauta, Nambudiri). Of the continuation of the Vedic tradition in a newer sense, Jeaneane D. Fowler writes
Ancient Iranian religion composed) initially in the 5th-century BC. Another Iranian source are royal inscriptions of the Achaemenid Empire made in the Old Persian (with Akkadian, Aramaic and Elamite translations). These inscriptions, in particular those of Darius I and his son Xerxes I, contain many references to religion. The fact that these are fixed in time and place make them particularly useful. Except from the Achaemenid inscriptions, there is no evidence that the Iranian religious compositions were written until the late Parthian or Sassanid period. This makes ancient Iranian religion the only major religion of the Middle East which has no written texts