Mussius Aemilianus probably was of Italian stock. His career in imperial service is documented up to 18 May 247 from an inscription recovered at
Fiumicino. Appointments he held up to that date include
praefectus vehiculorum trium provinciarum Galliarum,
procurator Alexandreae Pelusi and a third location (now lost),
procurator portus utriusque Ostiae.
Valerian appointed him
Praefectus of
Roman Egypt, a position he held from possibly as early as 256 to 261. While the primary concern of the governor of Egypt was to safeguard the harvest and delivery of grain to the populace of Rome, he had other responsibilities which included resuming the persecution of Christians that had started under his predecessor
Aurelius Appius Sabinus.
Eusebius preserves a letter of Bishop
Dionysius of Alexandria where the bishop documents his trial before Mussius Aemilianus for professing Christianity, for which he was exiled to Cephro in the Libyan Desert. A surviving papyrus, dated to 259/260, has been identified as an independent witness to this trial. == Usurpation ==