Dates & Origins
The founder of Zoroastrianism, Zarathushtra, or Zoroaster as the Greeks rendered the name, cannot be ascribed any precise date and dating is a hotly contested issue.
Academic opinion, which bases its case on linguistic analysis of the oldest texts (the Gathas), suggests a date roughly around 1300 BCE.
Other suggestions, based on Greek sources, arrive at dates as far apart as 6000 BCE and the sixth century BCE.
Furthermore, his exact place of origin cannot be pinpointed, although it is thought that he lived either in the part of Iran which is known as Azerbaijan today or possibly in what has been called Greater Iran, namely around Balkh, or possibly as far east as the Pamir mountains in today's Tajikistan.
All these areas are connected by a common Iranian culture and once upon a time practised Zoroastrianism.
It is widely accepted that the philosophy Zoroaster propounded was adopted by the Achaemenid kings (Cyrus, Cambyses, Darius, Xerxes, Artaxerxes etc) even though the first direct reference to Ahura Mazda, (the word used by Zoroaster in the Gathas to mean God), dates to Darius rather than to Cyrus.
Nevertheless, it is generally accepted that Cyrus’ ethos as expressed in the Cyrus cylinder was one of relative clemency and toleration towards his vanquished enemies which concords with the moral values taught by Zoroaster.
Three Iranian empires (mid 6 - mid 4th centuries BC, mid 2nd BC –mid 3rd AD & mid 3rd AD – mid 7th AD) spanning about 1000 years are known to have subscribed to and practised Zoroastrianism before the advent of Islam.