Of the two sons of Phraates, the first to mount the Parthian throne was Mithradates IV. However, his authority was soon disputed by Orodes II, whose illustrious general, Surena, eventually defeated and captured Mithradates. We are told by Justin (42.4.4) that charged with conspiracy against Parthia for seeking Roman assistance, Mithradates was at once executed on the order of Orodes.
KINGS of PARTHIA. Mithradates IV. 58/7 - 54/3 BC. AR Drachm (4.09 gm). Rhagae mint. Diademed bust left / BACILEΩC ΜΕΓΓΑΛΟΥ (sic) [A]P-CAKOΥ ΔΙΚΑΙΟΥ ΕΠΙΦΑΝΟΥC ΘΕΟΥΕΥΠΑΤΟΡΟΥ ΦΙΛΕΛΛΗΝΟ[C], Arsakes I seated right on throne, holding bow; monogram below bow. Sellwood 40.6 var. (legend); Shore -; BMC Parthia pg. 62, 9 var. (same); MACW -.
