The legitimate successors of Pacorus II: Osroes…

The legitimate successors of Pacorus II: Osroes I (105–116 and 117–129), Parthamaspates (116–117), and Mithridates IV (129–140), who ruled Mesopotamia, had been preoccupied by conflicts with the Romans, particularly the invasion by Roman emperor Trajan (98–117), and thus were unable to effectively challenge Vologases III.

Following the death of Osroes I, Vologases III had extended his rule through most of Parthia but had to contend with Mithridates IV, incursions of the nomadic Alans into Cappadocia, Armenia, and Media, and rebellion in Iran by an unknown usurper around 140.

The Parthian realm is finally reunited after Vologases III's death in 147 by Vologases IV (147–191), the son of his rival Mithridates IV.

Vologases III's Armenian kingship had been given to Sohaemus in 144, for unknown reasons.