[3][4] Aurelous was born in the Roman province of Dacia, north of the Danube, and prior to his military career served as a herdsman[5] as well as Master of the Imperial Horses ('Phronistes').

As a former Imperial Horsemaster, Aureolus developed a self-contained cavalry force to increase the effectiveness of the comitatus as a highly mobile field army under the Emperor's direct control.

The army of the Macriani, which first supported usurper Ingenuus and then Regalianus, included inmates from garrisons in Danubian provinces and was estimated to be at least 30,000 strong.

However, when the Goths and Heruls invaded the Danubian provinces with an enormous force in 268, Aureolus was not even a senior officer of the Imperial comitatus that accompanied the Emperor against the marauders.

Historians believe the longer-term consequences of Aureolus' rebellion opened Raetia to further invasion by the Alamanni who then went on to raid Italy itself in the early months of the reign of Claudius Gothicus.

Using the Imperial mint in Mediolanum, Aureolus had coins struck bearing Postumus's image as Emperor with appeals to the faith of his former comrades of the cavalry on the reverse.

Following the conspiracy by the Praetorian Prefect, together with Aurelius Heraclianus, Claudius and Aurelian which saw Gallienus murdered, Aureolus as one of the Thirty Tyrants is thought to have attempted to take power himself.