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 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