entirely free from defects. His creation, however, can only exist by
the free play and equilibrium of opposing forces, to which he gives
activity: the incompatibility of tendency displayed by these forces, and
their alternations of growth and decay, inspired the Iranians with the
idea that they were the result of two contradictory principles, the one
beneficent and good, the other adverse to everything emanating from the
former.*

* Spiegel, who at first considered that the Iranian dualism
was derived from polytheism, and was a preliminary stage in
the development of monotheism, held afterwards that a rigid
monotheism had preceded this dualism. The classical writers,
who knew Zoroastrianism at the height of its glory, never
suggested that the two principles might be derived from a
superior principle, nor that they were subject to such a
principle. The Iranian books themselves nowhere definitely
affirm that there existed a single principle distinct from
the two opposing principles.

In opposition to the god of light, they necessarily formed the idea of
a god of darkness, the god of the underworld, who presides over death,
Angrô-mainyus. The two opposing principles reigned at first, each in his
own domain, as rivals, but not as irreconcilable adversaries: they were
considered as in fixed opposition to each other, and as having coexisted
for ages without coming into actual conflict, separated as they were by
the intervening void. As long as the principle of good was content
to remain shut up inactive in his barren glory, the principle of evil
slumbered unconscious in a darkness that knew no beginning; but when
at last "the spirit who giveth increase"--Spentô-mainyus--determined to
manifest himself, the first throes of his vivifying activity roused from