Europe 284: Diocletian vs Carinus
When Carus’ youngest son and successor in the East, Numerian, died under suspicious circumstances, the eastern legions proclaimed the general Diocletian as emperor. At about the same time news of this usurpation reached Carus’ eldest son Carinus in Britain, revolts broke out in northern Italy and Pannonia under the leadership of either one or two men named Julianus.
The Agri Decumates was lost to the Romans in c.262, regained by Aurelian and Probus in 275–8, and lost again sometime between 290 and 310. The losses here seem not so much due to any rise in power of the local Alemanni tribe, but Roman internal division. When rival Roman factions controlled Gaul and Raetia, as was the case in 262–274 and 306, the limes of the Agri Decumates were no longer defensible and had to be abandoned.
?? 283–Nov 284 Co-principate of Numerian▲
Following the death of Carus, his son Numerian became ruler of the eastern Roman Empire, but almost immediately suffered a defeat at the hands of the Persians. Discouraged, Numerian marched back west through Syria and Asia Minor, but during the course of 284 fell ill and was placed in a closed litter by his father-in-law, the praetorian prefect Aper. In late November soldiers, disregarding Aper’s protests and suspicious at the smell of decay, broke into the litter to discover that Numerian had been dead for several days.
20 Nov 284 Diocletian’s revolt▲
Upon the discovery of the death of Numerian, an assembly and tribunal were organized, in which the low-born but popular general Diocles denounced Aper as the murderer and personally ran him through with his sword. Diocles was then proclaimed emperor by the troops, adopting the more Latinate name “Diocletian”. Despite his claim to be the avenger of Numerian, Diocletian rejected the rule of Carus’ other son Carinus and marched west to depose him.
284–285 Marcus Aurelius Julianus▲
In 284, inspired by news either of the death of Carus or of Numerian, Marcus Aurelius Julianus proclaimed himself emperor in Pannonia. Returning from Britain and Gaul, Carinus marched through Raetia and Noricum to successfully crush this usurper in Pannonia. This Julianus is known from the surprisingly large number of coins he minted at Siscia and a reference by the ancient historian Aurelius Victor. It is possible that he was the same person as Sabinus Julianus of northern Italy.
Dec 284–May 285 Sabinus Julianus▲
In late 284, upon learning of the death of Numerian, Carinus’ praetorian prefect Sabinus Julianus proclaimed himself emperor in northern Italy. Attacking from Pannonia, Carinus defeated and killed the usurper at Verona the following spring. This Julianus is known only from ancient historians and it is possible that he was the same person as Marcus Aurelius Julianus of Pannonia.