Together with the kidnapped Parthian prince Augustus had given in exchange for the legion standards captured by the Parthians at Carrhae in 53 BCE, he also had given Phraates IV an enslaved Italian girl, "Thea Muse", who has become Queen Musa of Parthia.

To ensure that her child Phraataces will inherit the throne without incident, Musa persuades Phraates IV, whose greatest enemies are his own family, to give his other five sons to Augustus as hostages, thus acknowledging his dependence on Rome.

Again, Augustus uses this as propaganda depicting the submission of Parthia to Rome; he will list it as a great accomplishment in his funerary inscription, Res Gestae Divi Augusti. (The hostages include Tiridates III, whom the Romans will later try to install as a vassal king in CE 35).

He appoints Phraates V successor and in about 2 BCE is murdered by Musa.