Praetorian prefecture of Gaul

The Praetorian Prefecture of Gaul (Latin: praefectura praetorio Galliarum) was one of four large prefectures into which the Late Roman Empire was divided in the 4th century. == History == The prefecture was established after the death of Constantine I in 337, when the empire was split up among his sons and Constantine II received the rule of the western provinces, with a praetorian prefect as his chief aide.

Source: Wikipedia — Praetorian prefecture of Gaul (CC BY-SA 4.0)