(Ἀρσάκης), the name of the founder of the Parthian empire, which was also borne by all his successors, who were hence called the Arsacidae. Pott (Etymologische Forschungen, ii. p. 172) supposes that it signifies the " Shah or King of the Arii ;" but it occurs as a Persian name long before the time of the Parthian kings. Aeschylus (Aesch. Pers. 957) speaks of an Arsaces, who perished in the expedition of Xerxes against Greece; and Ctesias (Pers. cc. 49, 53, 57, ed. Lion) says, that Arsaces was the original name of Artaxerxes Mnemon.