They were not overexposed militarily. After conquering and integrating the whole mediterranean basin they only had two rivaling neighbors: Germanic peoples at the north and the parthians-sassanid-persians in the east. In times of integrity they managed just fine. The only reason the germans survived history to hurt the empire was because the Antonine emperors didn&#x27;t want to genocide them.<p>Then the empire had a stint of epidemics and bad luck that degradated socitey and the political system, leading to constant civil war.