Hindu texts "Śruti" refers to the body of most authoritative, ancient religious texts, believed to be eternal knowledge authored neither by human nor divine agent but transmitted by sages ("rishis"). These comprise the central canon of Hinduism. It includes the four Vedas including its four types of embedded texts - the Samhitas, the Brahmanas, the Aranyakas and the early Upanishads. Of the "Shrutis" (Vedic corpus), the Upanishads alone are widely influential among Hindus, considered scriptures par excellence of Hinduism, and their central ideas have continued to influence its thoughts and traditions. The "Smriti" texts are a specific body of Hindu texts attributed
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