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 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.