Roman Britain is most familiar as a battleground for legions marching through the pages of ancient writers—Julius Caesar in his Gallic Wars (books IV and V) or Dio Cassius (c. 150–235 A.D.) in his History of Rome. The picture we get, often enough, is of a mighty empire subduing barbarous hordes. The Roman historian Tacitus (55–120 A.D.), for example, wrote a masterly tribute to his father-in-law, Julius Agricola, who had served as governor of Britain. Tacitus’s description of Britain, however, does little more than contrast the urbane sophistication of the conquering Roman with the raw simplicity of the native Briton.
Things had changed by the fourth century A.D. The last great Roman historian, Ammianus Marcellinus, describes the plight of wealthy, cultivated Britons faced by a secretpoliceman called Paul (a.k.a. “The Chain”), whom the emperor sent north to hunt down Rome’s enemies. There is no doubt that Ammianus’s readers would have identified not with the cruel, rapacious Paul but with the hapless provincials.