A vast empire once including part of Greece and reaching India in the east. It impinged on the Jews with the conquest of Cyrus over the Medes (550 BCE) and his decree authorizing the exiles to return from Babylon to Jerusalem, a decree reaffirmed by Darius I (Ezra 5: 1–6: 15). The legendary story of Esther is set in the reign of Ahasuerus, or Xerxes (Esther 1: 1–2). The empire was destroyed by Alexander the Great (c. 330 BCE). The Persians, regarded as barbarous orientals in many Greek sources, are always treated favourably in the OT.

The religion of Zoroaster (7th cent. BCE) had its origin and base in Persia; its belief was that the god of Light, Ahura Mazda, had overcome Ahriman (darkness) and this dualism has been thought to have had an influence on Judaism, as did also its developed system of angels. It was a religion which was tolerant of other cults, and the Greek Apollo and the Jews' Yahweh were among the deities recognized.