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
Phenomenology of religion the authentic sources: writings and images by the believers themselves. This procedure compelled him to reduce the field of his research - he had to profoundly master all relating languages and writings in order to be able to understand his sources in a way as they would have wanted to be understood themselves. Consequently, he reduced his field of research to the phenomena in religions living around the origin of Christianity: during the millennia before and the centuries after Christ, in Iran (Avesta), Babylonia and Assyria, Israel, Egypt, Greece and Rome. The required knowledge of speeches, also, is one of