Indian religions Brahmanas and the older Upanishads (both presented as discussions on the rituals, mantras and concepts found in the four Vedas), which today are some of the most important canonical texts of Hinduism, and are the codification of much of what developed into the core beliefs of Hinduism. Some modern Hindu scholars use the "Vedic religion" synonymously with "Hinduism." According to Sundararajan, Hinduism is also known as the Vedic religion. Other authors state that the Vedas contain "the fundamental truths about Hindu Dharma" which is called "the modern version of the ancient Vedic Dharma" The Arya Samajis recognize the Vedic religion
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.