Associated with: Zoroastrianism, Manichaeism
Also known as: Angra (Anghra) Mainyu
Earliest recorded mention: Uncertain, but believed to be c. 1200 BCE
Major texts: Avesta, Pahlavi texts (the Bundahishn, the Book of Arda Viraf, Jamasp Nameh)
Zoroastrianism, the religion expounded by the prophet Zarathustra (Zoroaster), was the dominant religion of the Persian Empire (c. 550-330 BCE). It was the most widely-practiced world religion during the life of Jesus, and still has many adherents in Iran and India. The 1907 Catholic Encyclopedia offers "Parsee" (Parsi) as a synonym for Zoroastrian, but Parsi is only one of the major communities within Zoroastrianism.
Zoroastrians worship Ahura Mazda (Ohrmazd), the creator of the universe and a source of only good. Evil in the world comes from Ahriman, or Angra Mainyu, the "destructive spirit" or "angry man" that is the exact opposite of Ahura Mazda. In various parts of the Avesta, Ahriman rules the nether world and is the chief (though not the creator) of the daevas, false gods that personify evil.
The Zurvanite sect of Zoroastrianism posits that Ahura Mazda and Ahriman were born as twins, and that Ahriman chose evil. The Zurvanite creation myth says that Ahriman was born of Zurvan (Time, the First Principle)'s doubt. Zarathustra prophesied that Ahura Mazda would ultimately defeat Ahriman, not only because his powers are superior (Ahura Mazda is omniscient; Ahriman is not) but because humans will choose good over evil.
In the third century, the Persian prophet Mani synthesized the principal teachings of Zoroastrianism, Christianity and Buddhism into a single faith. In Manichaeism, widely practiced between the third and seventh centuries, Ahriman rules the World of Darkness, composed of five evil kingdoms. He is the father of a son, Az, who in turn is the father of Adam and Eve — born after Az swallowed huge quantities of light. Adam and Eve, therefore, are the products of both light and darkness, with the freedom to choose between them.
This power of free will is a distinguishing element of Zoroastrianism, which, along with Judaism, was one of the first religions to recognize humans' ability to choose between good and evil. Ahriman answers the fundamental question, "Why does evil exist?" without forcing believers to see the universe itself as evil. The universe itself is good, but evil exists within it and outside it, a constant challenge. Likewise, we as humans are beings filled with light, though heirs to darkness. Therefore we all, as individuals, have not only the power but the responsibility to choose between the two. Zoroastrianism teaches that light will ultimately triumph, and that Ahriman's eventual defeat is inevitable — but "ultimately," as we see, is a long time coming.