In the first half of the second century, the Parthian Empire had been divided, but king Vologases IV had reunited it. In 180, he managed to make his son, Vologases V, king of Armenia. In 191, Vologases IV died and Vologases V became king of the Parthian Empire.
At that moment, there was a rebellion going on in Media, where Osroes II was minting coins of his own in Ecbatana. The new but experienced ruler of Parthia, however, appears to have overcome the rebel quite quickly: his coinage comes to an end almost immediately after the accession of Vologases V.
The chronology of the Arsacid kings of the Parthian Empire is less well-understood than, for example, the sequence of Seleucid and Ptolemaic kings or the emperors of Rome. This information is based on the researches by G.R.F. Assar, as published in "Iran under the Arsakids, 247 BC – AD 224/227" in: Numismatic Art of Persia (2011).