It was part of their higher allegiance to the King of kings.
Thus their sovereign styles himself the king of kings and the king of the lands that is to say, of the whole civilized world.
Arsacids now began to assume the old title king of kings (the s/iahanshah of modern Persia),though previously their coins, as a rule, had borne only the legend great king.
This tact is the clearest symptom of the inner weakness of Character of their empire and of the small power wielded by the the Parthian king of kings.
The Arsacids assume the title king of kings and derive their line from Artaxerxes II.
