During the Roman Empire, the governor of Roman Egypt (praefectus Aegypti) was a prefect who administered the Roman province of Egypt with the delegated authority (imperium) of the emperor. Egypt was established as a Roman province in consequence of the Battle of Actium, where Cleopatra as the last independent ruler of Egypt and her Roman ally Mark Antony were defeated by Octavian, the adopted heir of the assassinated Roman dictator Julius Caesar. 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