Their choice fell upon Zamasp, a brother of Kobad, who was noted for his love of justice and for the mildness of his disposition.
The necessary arrangements having been made, they broke out into universal insurrection, arrested Kobad, and committed him to safe custody in the "Castle of Oblivion," proclaimed Zamasp, and crowned him king with all the usual formalities.

An attempt was then made to deal the new religion a fatal blow by the seizure and execution of the heresiarch, Mazdak.

But here the counter-revolution failed.

Mazdak was seized indeed and imprisoned; but his followers rose at once, broke open his prison doors, and set him at liberty.

The government felt itself too weak to insist on its intended policy of coercion.