Ammianus Marcellinus, who lived from ca. A.D. 330 until ca. A.D. 395, was the last true Roman historian. His Res gestae (History) was intended to be a continuation of the historian Cornelius Tacitus, whose own History had ended with the reign of Domitian (A.D. 80-96). Ammianus's history was written in thirty-one books and covered the period from the accession of the emperor Nerva in A.D. 96 to the Battle of Adrianople and the death of the emperor Valens in A.D. 378. Of these, only the books commencing with A.D. 353 and dealing with Ammianus's own times (books 14-31) have survived. The thirteen lost books, which covered a period of 258 years, could have provided little more than an overview of the times, and this probability also may explain why they were lost, and the others were preserved.

Little is known about Ammianus and his attitudes except for what...