Hindu texts Vedas: the Rigveda, the Yajurveda, the Samaveda and the Atharvaveda. Each Veda has been subclassified into four major text types – the Samhitas (mantras and benedictions), the Aranyakas (text on rituals, ceremonies, sacrifices and symbolic-sacrifices), the Brahmanas (commentaries on rituals, ceremonies and sacrifices), and the Upanishads (text discussing meditation, philosophy and spiritual knowledge). The Upanishads are a collection of Hindu texts which contain some of the central philosophical concepts of Hinduism. The Upanishads are commonly referred to as "Vedānta", variously interpreted to mean either the "last chapters, parts of the Veda" or "the object, the highest purpose of the Veda".
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.