 As noted, the epigraph from "Claudiopolis" (above) is generally interpreted to mean that Probus had taken on the role of "Praefectus Aegypti" before the end of 269 AD.Ever since Augustus' conquest of Egypt in the first century BC, the emperors of Rome had regarded their absolute control of this territory and its grain harvests as a "sine qua non" for the maintenance of their authority.Loss of control of Egypt would almost immediately undermine the Imperial government's ability to maintain control of the Roman people.