Procopius of Caesarea has written the history of the wars which Justinian, Emperor of the Romans, waged against the barbarians of the East and of the West, relating separately the events of each one, to the end that the long course of time may not overwhelm deeds of singular importance through lack of a record, and thus abandon them to oblivion and utterly obliterate them. The memory of these events he deemed would be a great thing and most helpful to men of the present time, and to future generations as well, in case time should ever again place men under a similar stress. For men who purpose to enter upon a war or are preparing themselves for any kind of struggle may derive some benefit from a narrative of a similar situation in history, inasmuch as this discloses the final result attained by men of an earlier day in a struggle of the same sort, and foreshadows, at least for those who are most prudent in planning, what outcome present events will probably have. Furthermore he had assurance that he was especially competent to write the history of these events, if for no other reason, because it fell to his lot, when appointed adviser to the general Belisarius, to be an eye-witness of practically all the events to be described. It was his conviction that while cleverness is appropriate to rhetoric, and inventiveness to poetry, truth alone is appropriate to history. In accordance with this principle he has not concealed the failures of even his most intimate acquaintances, but has written down with complete accuracy everything which befell those concerned, whether it happened to be done well or ill by them.