In the Late Roman Empire, usually dated 284 AD to 641 AD, the regional governance district known as the Roman or civil diocese was made up of a grouping of provinces each headed by a Vicarius, who were the representatives of praetorian prefects (who governed directly the dioceses they were resident in). There were initially twelve dioceses, rising to fourteen by the end of the 4th century.
The term diocese comes from the Latin: dioecēsis, which derives from the Greek: dioíkēsis (διοίκησις) meaning "administration", "management", "assize district", or "group of provinces".