_Condition of the Persians under the Successors of Alexander--under the Arsacidce. Favor shown them by the latter--allowed to have Kings of their own. Their Religion at first held in honor. Power of their Priests. Gradual Change of Policy on the part of the Parthian Monarchs, and final Oppression of the Magi. Causes which produced the Insurrection of Artaxerxes._