4. One of the chief satraps or governors among the Parthians, though, from his name, evidently of Greek origin, at the time when Tiridates, supported by Tiberius and the Roman influence, invaded Parthia, A. D. 36. After wavering for some time between the two rivals, Hieron declared in favour of Artabanus, and was mainly instrumental in re-establishing him upon the throne. (Tac. Ann. 6.42, 43.)