1 “Ahura Mazda displayed the omniscient wisdom to Zoroaster, and through it He beheld the root of a tree, on which were four branches, one golden, one of silver, one of steel, and one was mixed up with iron. … 3. Ahura Mazda spoke to Zartosht the Spitaman4 thus: ‘That root of a tree which thou sawest, and those four branches, are the four periods which will come.”-Zand-I Wahman Yasn, Chapter 1