Marcus Aurelius Carus (c. AD 223-83), Roman Emperor, 282-83, born at Narona in Illyricum. A senator and prefect of the praetorian guard, he was proclaimed emperor by the troops after the murder of Probus. Leaving his elder son Carinus to govern the western provinces, he started out with his younger, Numerianus, on an expedition against the Persians. After successful campaigns against the Quadi and Sarmatians on the Danube, he then conquered Mesopotamia and crossed the Tigris. Here he was assassinated, probably at the instigation of the praetorian prefect, Arrius Aper.