High Quality Content by WIKIPEDIA articles! Vologases IV of Parthia ruled the Parthian Empire from 147 to 191. The son of Mithridates IV of Parthia (129 140), he united the two halves of the empire which had been split between his father and Vologases III of Parthia (105 147). He also reconquered the kingdom of Characene which seems to have been independent since the Roman invasion of the Parthian empire under Trajan (98 117). Vologases IV may be the king Volgash of the Zoroastrian tradition, who began the gathering of the writings of Zoroaster.