"Zoroastrianism," for more than a thousand years the dominant religion of Persia, is founded on the teachings of the prophet Zarathustra. (Zoroaster is an often used version of his name, and from it the name of the religion is derived; this version reflects ancient Greek transliteration.) Four main stages in the religion's history can be distinguished: the early faith as promulgated by Zarathustra himself; the religion of the Persian Empire under Darius I (who ruled 521–486 BCE) and his Achaemenid successors; its renewal under the Arsacid (250 BCE–226 CE) and Sassanian (226–641) dynasties; and the late period, when the religion was swamped by Islam but continued as the faith of a minority, some of whom settled in India and are known as Parsis (literally "Persians").

Scriptures

The scriptures are known as the Avesta (or Zend-Avesta) and consist of various hymns, treatises, and poems. They comprise the Yasna, a collection of liturgical...