Kobad, who had nothing to gain from embracing a creed which levelled him with his subjects, and was scarcely compatible with the continuance of monarchical rule, must have been sincere in his profession; and we inquire with interest, what were the circumstances which enabled Mazdak to attach to his cause so important and so unlikely a convert.
The explanation wherewith we are furnished by our authorities is, that Mazdak claimed to authenticate his mission by the possession and exhibition of miraculous powers.

In order to impose on the weak mind of Kobad he arranged and carried into act an elaborate and clever imposture.

He excavated a cave below the fire-altar, on which he was in the habit of offering, and contrived to pass a tube from the cavern to the upper surface of the altar, where the sacred flame was maintained perpetually.

Having then placed a confederate in the cavern, he invited the attendance of Kobad, and in his presence appeared to hold converse with the fire itself, which the Persians viewed as the symbol and embodiment of divinity.

The king accepted the miracle as an absolute proof of the divine authority of the new teacher, and became thenceforth his zealous adherent and follower.
It may be readily imagined that the conversion of the monarch to such a creed was, under a despotic government, the prelude to disorders, which soon became intolerable.