supreme; but after that time the nobles, then firmly rooted and grown wealthy from lands and war, began to usurp more and more authority. Their defiance of the king brought about frequent periods of disruption and eventually the downfall of the empire. Very probably the decline of the royal power and the rise of the nobles were closely connected with the religious revival of the latter half of the first century after Christ. Parallels for the struggle between the nobles and Magi on one hand and the king on the other can easily be found in Achaemenian and Sasanian history.
Some years before the death of Mithradates II in 87 b.c. he had carved on the rock at Behistun a relief in which he and his principal officials appear. The chief of these is called satrap of satraps, the other three simply satraps. Probably these men belonged to the great families of Iran such as the Surens and Karens. Their positions with attendant rights and duties gradually became hereditary. A Suren always placed the crown upon the head of a new king, and, as at Carrhae, a Suren frequently led the Parthian armies in battle.
Evidently the form of government of Parthian dependencies varied widely and changed from time to time. Mithradates apparently appointed a governor to rule over newly conquered Media; Himerus served in the same capacity in Babylonia; and at a later date Mesopotamia was governed by this method. In other
