Marcus Aurelius Equitius Probus was born at Sirmium on 19 August AD 232.
Probus' early military career is largely unknown. He most likely rose through the ranks, achieving considerable skill in commanding troops. Under Aurelian he was said to be the emperor's most outstanding commander. During that time, he defended the embattled Rhine frontier against the Alemanni.
When Tacitus had died in AD 276, Probus refused to accept Florian's claim to the imperial throne. Far more, he claimed he was the man to whom Tacitus had promised the succession.
Florian controlled the far larger army and marched on him. Their forces met near Tarsus. But at this point Probus' excellent military ability won through. He avoided a direct confrontation and used the stifling summer heat of the Middle East, to which Florian's European troops weren't accustomed, to his advantage.
Probus then set out for Rome, where the senate confirmed him as emperor. And in turn the new emperor was careful to show great respect toward the senate. Under the new emperor's regime the surviving murderers of Aurelian were executed.
Next Probus needed to address the situation along Rome's frontiers. After the death of Aurelian, a series of attacks had taken place. Tacitus and Florian had largely dealt with the Gothic attack on Asia Minor (Turkey), but the German invasion across the Rhine had so far not been dealt with.
For the next two years Probus would be on campaign against the Germans. The Franks, the Longiones, the Burgundians and the Vandals were all defeated, despite their huge numbers.
In AD 278 Probus defeated yet another invasion by the Vandals.
In AD 279 the emperor set out for the east to deal with troubles having arisen there. The Moorish governor of Syria, Julius Saturninus, had declared himself emperor. On the way he repelled an invasion by the tribe of the Getae, who had crossed the lower Danube. Meanwhile the usurper Saturninus was killed either by his own soldiers or by assassins sent by the emperor. With his challenger dead, Probus next moved against brigands who fiercely defended themselves against the siege to their mountain fortress of Cremna in Isauria, but eventually were defeated.
Apart from the revolt of Saturninus, Probus' main reason for travelling east was a desire to reconquer Mesopotamia. But once on the scene he deemed it unwise to begin a war with the Persians and instead came to a truce with Persian King Bahram II whereby both sides reassured each other of holding the peace (AD 279).
It might have been that Probus deemed the Persians too strong. But it probably is more likely that he decided the troublesome barbarians on the northern frontiers and possibly mutinous provincial governors demanded all his attention and hence made any action against the Persians impossible.
As he travelled back west, while passing through Thrace he agreed to settle 100'000 Scythians from the tribe of the Bastarnae in the area.
Soon after his presence was required in the west.
Toward the end of AD 281 Probus returned to Rome and held a triumph to mark his achievements. In the spring of AD 282 he headed for Sirmium on the Danube from where he alas hoped to prepare a campaign against Persians.
But morale in the army was by now very low. When not campaigning against barbarians or rebels, Probus had put them to work. They had been made to drain land, erect buildings and defences, build bridges, even plant vineyards.
The praetorian prefect Marcus Aurelius Carus was proclaimed emperor in September AD 282 by the armies stationed in Raetia and Noricum along the Upper Danube.
Probus, on hearing the news, immediately sent troops to engage Carus, defected to the other camp.
Probus was murdered by his own troops not far from his birth place Sirmium in late September AD 282.