Around 260 the frontiers of the empire suddenly collapsed, from Persia in the East to Gaul in the West the empire was in danger. The fighting Roman armies began to hail their respective commanders as emperors.

Aurelius became emperor in 270 and quickly set to restore Roman authority in Europe and Asia Minor. He drove the barbarians out from Italy, and brought Gaul, Spain, and Britian back into the empire.

In Rome he increased the distribution of food, and he tried to subordinate the divergent religion of the empire to the Baal cult with himself as God. After ruling from 270 to 275, he was killed by army officers.