He was not a professional man of letters but an army officer of Greek origin born at Antioch and contemporary with the events described in what remains of his work. He set himself the task of continuing the histories of Tacitus from A.D. 96 down to his own day. The first thirteen of his thirty-one books are lost; the remainder describe a period of only twenty-five years (A.D. 354-378) and the reigns of the emperors Constantis, Julian, Jovian, Valentinian and Valens, for which he is a prime authority. He was a pagan and an admirer of the apostate Julian, to whose career about half the surviving books are devoted. Nevertheless, his treatment of Christianity is free from prejudice and his impartiality and good judgement have been generally acknowledged.
Ammianus Marcellinus (c. 330 - after 391) is the preeminent historian of the Late Roman Empire, whose extant work forms the most important narrative we possess on the Fourth Century A.D. Born of genteel extraction in a Greek-speaking part of the empire, Ammianus served in the army in campaigns ranging form Gaul to Persia before settling in Rome and beginning his literary carreer. Besides shedding light on many events from the reign of Constantius to the calamitous defeat at Adrianople - including striking portraits of emperors Julian and Valentinian - his work offers as well a compelling description of Late Roman society.