THE “HISTORY OF ROME,” written by Ammianus Marcellinus, consisted of thirty-one books beginning with the period of the accession of Nerva and extending to the death of Valens. The eighteen books which survive begin with the seventeenth year of the reign of Constantine and do not go beyond the year 378. Gibbon calls Marcellinus an “accurate and faithful guide who composed the history of his own time without indulging the prejudices and passion which usually affect the mind of a contemporary”—certainly a high compliment which few historians have deserved. Marcellinus was born at Antioch in Syria and began life as a soldier, entering the service of the Emperor Constantius in the year 350, and serving under him several campaigns. He also accompanied the expedition of the Emperor Julian into Persia. After leaving the army he went to Rome and devoted the rest of his life chiefly to his “History.” Little or nothing is known of him beyond this, except that he was still living as late as the year 380 A.D. The dates of his birth and death are both conjectural.