When Theoderic the Great entered the city of Rome in 500, as an Ostrogothic king, the citizens in Rome could have been forgiven for thinking an Emperor had returned. Everything he did, from his journey, to his arrival, and actions in the city itself, were in imitation of Roman expressions of imperial power. The role of the Emperor, however, remains complex and multifaceted, and the very powers Theoderic was seeking to emulate had complex histories of their own. It was only when Augustus, Rome’s first Emperor, died in 14 AD that Rome at last admitted the truth that a Princeps now ruled,...