 Octavian then rose to supreme power with the title Augustus, ending the era of the Roman Republic and installing himself as "princeps", the so-called "leading citizen" of Rome who in fact acted as an autocratic ruler.Although senators continued to serve as governors of most other provinces (the senatorial provinces), especially those annexed under the Republic, the role of Egypt during the civil war with Antony and its strategic and economic importance prompted Augustus to ensure that no rival could secure "Aegyptus" as an asset.He thus established Egypt as an imperial province, to be governed by a prefect he appointed from men of the equestrian order.