Apollinaris IV, Praetorian Prefect of Gaul

He Prefect of Gaul under Valentinian III (425-455).

Military of ancient Rome 753 BC – AD 476

Praetorian prefect (Latin: praefectus praetorio, Greek: ἔπαρχος/ὕπαρχος τῶν πραιτωρίων) was the title of a high office in the Roman Empire. Originating as the commander of the Praetorian Guard, the office gradually acquired extensive legal and administrative functions, with its holders becoming the Emperor's chief aides. Under Constantine I, the office was much reduced in power and transformed into a purely civilian administrative post, while under his successors, territorially-defined praetorian prefectures emerged as the highest-level administrative division of the Empire. The prefects again functioned as the chief ministers of the state, with many laws addressed to them by name. In this role, praetorian prefects continued to be appointed until the reign of Heraclius, when wide-ranging reforms reduced its power and converted it to a mere overseer of provincial administration. The last traces of the prefect disappeared in the Byzantine Empire in the 840s.

The term praefectus praetorio was often abbreviated in inscriptions as 'PR PR'.[1]