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 in the ancient period. The religious information was rather oral both in composition and transmission. The non-Iranian sources are mainly Greek. The most important Greek source is Herodotus. Some of the Greek information on ancient Iranian religion is however unreliable. This is either because it is based on outright wrong information or based on misunderstandings. The historical reconstruction of ancient Vedic literature is also an important source. The earliest religious texts of the related Indo-Aryan peoples are indispensable for reconstructing the historical development of the ancient Iranian religion. The most important of these texts in this regard is the Rigveda.