The same causes which had corrupted Zoroastrianism in Media soon after the establishment of the Empire, worked also, though more slowly, in Persia, and a large section of the nation was probably weaned from its own belief, and won over to Magism, before Cambyses went into Egypt.

His prolonged absence in that country brought matters to a crisis.

The Magi took advantage of it to attempt a substitution of Magism for Zoroastrianism as the religion of the state.

When this attempt failed, there was no doubt a reaction for a time, and Zoroastrianism thought itself triumphant.

But a foe is generally most dangerous when he is despised.