On August 9, 378 AD, the Eastern Roman emperor Valens led his army against a Gothic force near Adrianople in Thrace — modern Edirne in northwestern Turkey — and was killed along with roughly two-thirds of his army. The Battle of Adrianople was not the largest Roman defeat in history; Cannae killed more Romans in a single afternoon. It was not the most strategically complex engagement the Romans ever fought; the tactics were relatively straightforward. What made it consequential was not the battle itself but what came before it and what followed from it, the chain of decisions and consequences that makes Adrianople one of the pivots of late Roman history.

The kingdoms that replaced Roman administration in the western provinces were not anti-Roman. This is the most important correction to the standard narrative of Rome’s fall, and it matters because the standard narrative — civilized Rome overwhelmed by barbarous outsiders — is both factually wrong and interpretively misleading. The Visigothic kingdom in Spain, the Ostrogothic kingdom in Italy, the Burgundian kingdom in the Rhône valley, the Frankish kingdom in Gaul — these were not negations of Rome. They were, in varying degrees, continuations of Rome under different management, sustained by Roman administrative forms, legitimated by Roman imperial titles, and often governed by rulers who had spent significant portions of their careers in Roman service and who regarded Roman civilization as the culture they had inherited rather than the culture they had defeated.