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
Bahá'í Faith and the unity of religion consider a successor to Zoroaster, Abraham, Moses, Jesus, Muhammad, Krishna and Buddha. This acceptance of other religious founders has encouraged some to regard the Bahá'í religion as a syncretic faith. However, Bahá'ís and the Bahá'í writings explicitly reject this view. Bahá'ís consider Bahá'u'lláh's revelation an independent, though related, revelation from God. Its relationship to previous dispensations is seen as analogous to the relationship of Christianity to Judaism. They regard beliefs held in common as evidence of truth, progressively revealed by God throughout human history, and culminating in (at present) the Bahá'í revelation. Bahá'ís have their own sacred scripture, interpretations, laws