My intention in writing this book has been to demonstrate the unique importance of Ravenna in the history of Italy and of Europe, especially during the Dark Age from the time of Alaric's first descent into the Cisalpine plain to the coming of Charlemagne. That importance, as it seems to me, has been wholly or almost wholly misunderstood, and certainly, as I understand it, has never been explained. In this book, which is offered to the public not without a keen sense of its inadequacy, I have tried to show in as clear a manner as was at my command, what Ravenna really was in the political geography of the empire, and to explain the part that position allowed her to play in the great tragedy of the decline and fall of the Roman administration. If I have succeeded in this I am amply repaid for all the labour the book has cost me. The principal sources, both ancient and modern, which I have consulted in the preparation of this volume have been cited, but I must here acknowledge the special debt I owe to the late Dr. Hodgkin, to Professor Diehl, to Dr. Corrado Ricci, and to the many contributors to the various Italian Bollettini which I have ransacked.