If you think you’re living in an era of stagnation and decline, look back to 5th-century Rome, when the Western Roman Empire began to shift from mere decay to full-on disintegration. Borders became porous, emperors came and went with alarming rapidity, and provinces that had once known Roman law and order were overcome by barbarian armies. Moreover, theological controversy and strange teachings emerged and spread throughout the Christian world, both East and West. It was what we now call late antiquity, and the ancient world was ending.