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
Definition of religion book "The Varieties of Religious Experience", the psychologist William James defined religion as "the feelings, acts, and experiences of individual men in their solitude, so far as they apprehend themselves to stand in relation to whatever they may consider the divine". By the term divine James meant "any object that is god"like", whether it be a concrete deity or not" to which the individual feels impelled to respond with solemnity and gravity. The sociologist Émile Durkheim, in his seminal book "The Elementary Forms of the Religious Life", defined religion as a "unified system of beliefs and practices relative to sacred