Hindu texts to an author, as a derivative work they are considered less authoritative than "Sruti" in Hinduism. The Smrti literature is a vast corpus of diverse texts, and includes but is not limited to Vedāngas, the Hindu epics, the Sutras and Shastras, the texts of Hindu philosophies, the Puranas, the Kāvya or poetical literature, the "Bhasyas", and numerous "Nibandhas" (digests) covering politics, ethics, culture, arts and society. Many ancient and medieval Hindu texts were composed in Sanskrit, many others in regional Indian languages. In modern times, most ancient texts have been translated into other Indian languages and some in Western languages.
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