nyus (the white spirit), Armaiti (the earth, or
also the spirit of piety), and of the hero-spirits Sraosha, Traetona,
which as light and darkness are distinguished from Angro (the black
spirit).

Later, as it seems, the theology and worship of the neighboring nomadic
Arya penetrated to these nations, and caused a religious conflict which
ended with the migration of Arya to the south. At this period
Zarathustra[2] (Zoroaster) came forward under the Bactrian priest and
King Kava Vistaspa, as defender and reformer of the religion of the
fathers against the encroachments of a strange doctrine. The Devas
(Zend, Dews) or the gods of the Indian Veda appear with Zarathustra as
evil spirits. Not Indra, but the hero Traetona, wages war with Ahi
(Zend, Azhi), while the kavis, or priests, are attacked by him as
deceivers and liars. From the belief in good spirits (Ahuras, i.e.,
the living, and Mazdas, i.e., the wise), the ancient genii of the
country, Zarathustra developed the belief of one highest God,
Ahura-Mazda (Ormuzd, Greek, [Greek: Osompzes]), a doctrine which he
received by divine inspiration through the mediation of the spirit
Srasha. Ahura-Mazda, surrounded by the Amesha-Spenta (Amshaspands), or
the holy immortals, not until later reduced to seven, is the creator of
light and life. The hurtful and evil, on the contrary, is non-existence
(akem), and in the oldest parts of the Avesta, the Gathas, which go back
to Zarathustra and his first followers, is not yet conceived as a
personal being. First in the Vendidad, written after Zarathustra, does
Angro-mainyus (Ahriman), or the evil one, with his Dews, although
subordinated to Ahura-Mazda, gain a place in the Iranian conception of
the universe, as the adversary of Ahura-Mazda, and as the cause of evil
in the natural and spiritual world. From these conceptions there was
developed in the later Parsism the system of the four periods of the
world, each of three thousand years, in the book "Bundehesh." In the
first period, Ahura-Mazda appears as creator of the world and as the
source of good. The creation, completed by Ahura-Mazda in six days by
means of the word (Honover), is in the second period destroyed by
Angro-mainyus, who, appearing upon the earth in the form of a serpent,
seduces the first human pair, created by Ahura-Mazda. In the third
period, which begins with the revelation given to Zarathustra,
Ahura-mazda and Angro-mainyus strive together for man. After this
follows