Carus, whose name before the accession may have been Marcus Numerius Carus, was born, according to differing accounts, either in Gaul, Illyricum or Africa. Modern scholarship inclines to the former view, placing his birth at Narbo (modern Narbonne) in Gaul though he was educated in Rome. Little can be said with certainty of his life and rule. Due to the decline of literature, the arts, and the want of any good historians of that age, what is known is almost invariably involved in contradiction and doubt. He was apparently a senator and filled various posts, bith civil and military before being appointed prefect of the Praetorian Guard by the emperor Probus in 282.
After the murder of Probus at Sirmium, Carus was proclaimed emperor by the soldiers. Although Carus severely avenged the death of Probus, he was suspected as an accessory to the deed. He does not seem to have returned to Rome after his accession, contenting himself with an announcement to the Senate. This was a marked departure from the constitutionalism of his immediate predecessors, Tacitus and Probus, who at least outwardly respected the authority of the senate, and was the precursor to the formal establishment of military autocracy under Diocletian.
Campaign against the Sassanids and death
Bestowing the title of Caesar upon his sons Carinus and Numerian, he left Carinus in charge of the western portion of the empire to look after some disturbances in Gaul  and took Numerian with him on an expedition against the Persians, which had been contemplated by Probus. Having inflicted a signal defeat on the Quadi and Sarmatians on the Danube, for which he was given the title Germanicus Maximus, Carus proceeded through Thrace and Asia Minor, annexed Mesopotamia, pressed on to Seleucia and Ctesiphon, and marched his soldiers beyond the Tigris.
The Sassanid King Bahram II, limited by internal opposition and his troops occupied with a campaign in modern-day Afghanistan, could not effectively defend his territory. The victories of Carus avenged all the previous defeats suffered by the Romans against the Sassanids, and he received the title of Persicus Maximus.
Rome's hopes of further conquest were cut short by his death, which occurred during a violent storm. His death was variously attributed to disease, the effects of lightning, a wound received in the campaign against the Persians, or an assassination planned by his Praetorian prefect, Lucius Flavius Aper. According to a letter to the praefect of Rome from Carus' personal secretary, transcribed in the Augustan History, Carus died of a commonplace illness, but the firing of his tent by his servants, who were maddened by grief, and the violence of the storm which raged over the camp at the hour of his death gave rise to its attribution to lightning, which was generally accepted. The fact that he was leading a victorious campaign, and his son Numerian succeeded him without opposition, suggest that his death was indeed a natural one.