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 was strongly connected. Beginning in the early 10th-century BC, the ancient Iranian religion was gradually displaced by Zoroastrianism, which contains many essential aspects of its predecessor. The sources on ancient Iranian religion, though limited, consist of textual and material sources. The textual sources are both Iranian and non-Iranian. An important Iranian source is the Avesta, which are Zoroastrian sacred scriptures made in the Avestan. This is considered the principal source of knowledge on ancient Iranian religions. It is a collection of several texts that seems to have been over a large span of time by a variety of authors. These