Odaenathus' Roman titles, such as "dux Romanorum", "corrector totius orientis" and "imperator totius orientis" differed from his royal eastern ones because the Roman ranks were not hereditary. Vaballathus had a legitimate claim to his royal titles, but had no right to the Roman ones—especially "corrector" (denoting a senior military and provincial commander in the Roman system), which Zenobia used for her son in his earliest known inscriptions with "King of Kings". Although the Roman emperors accepted the royal succession, the assumption of Roman military rank antagonized the empire. Emperor Gallienus may have decided to intervene in an attempt to regain central authority; according to the "Augustan History", praetorian prefect Aurelius Heraclianus was dispatched to assert imperial authority over the east and was repelled by the Palmyrene army. The account is doubtful, however, since Heraclianus participated in Gallienus' assassination in 268. Odaenathus was assassinated shortly before the emperor, and Heraclianus would have been unable to be sent to the East, fight the Palmyrenes and return to the West in time to become involved in the conspiracy against the emperor.