A year after Geta's death Caracalla left Rome never to return. He traveled throughout the eastern provinces overseeing the murder of thousands. In Alexandria, for example, he ordered a general massacre killing several thousand for no reason. And so the empire under Caracalla degraded further as Gibbon tells us:
The liberality of the father has been restrained by prudence, and his indulgence to the troops was tempered by firmness and authority. The careless profusion of the son was the policy of one reign, and the inevitable ruin both of the army and the empire. The vigor of the soldiers, instead of being confirmed by the severe discipline of camps, melted away in the luxury of cities.