The eagle standard of
IIII Flavia Felix (©!!)
In 193, after the death of the emperor Publius Helvius Pertinax, the Romans fought a civil war, in which the legions of the Danube supported Lucius Septimius Severus, the governor of Pannonia Superior, against Pescennius Niger of Syria and Clodius Albinus of the western provinces. Severus was successful and was to rule until 211. He finished the Parthian war that had been started by Lucius Verus. Again, II Adiutrix was transferred to Mesopotamia, and again, a subunit of IIII Flavia Felix occupied Budapest. That another subunit actually joined the eastern campaign has been assumed, because an inion proves the presence of a soldier at Alexandria in Troas in northwestern Turkey. However, more evidence is needed, because Alexandria is within the normal radius of the legion's civil activities.
In the third century, several wars were fought against the successors of the Parthians, the Sasanian Persians. That IIII Flavia Felix took part in at least one campaign is likely, because a tombstone of a legionary has been found as far away from Belgrade as Cyrrus in Syria. An inion from Speyer on the Middle Rhine must belong to one of the wars against the Alamanni (that of Caracalla in 213; Severus Alexander in 235; or Maximinus Thrax in 235-236); again, a subunit of IIII Flavia Felix must have left Moesia Superior.