Jan den Boeft

The last book of Ammianus Marcellinus' Res Gestae is the most important source for a momentous event in European history: the invasion of the Goths across the Danube border into the Roman Empire and the ensuing battle of Adrianople (378 CE), in which a Roman army was annihilated and the emperor Valens lost his life. Many contemporaries were of the opinion that this defeat heralded the decline of the Empire. Ammianus is sharply critical of the way Valens and his generals handled the military situation, but holds on to his belief in the permanence of Roma Aeterna, reminding his readers of earlier crises from which the Empire had recovered and pointing to the incompetence of the barbarians in siege craft.

The first part of Book 30 of Ammianus Marcellinus' Res Gestae is devoted to the military and diplomatic struggle for Armenia between Valens, emperor of the East, and king Sapor II of Persia. The Romans successfully defend their position, until they are forced to deal with the Goths who threaten to cross the Danube border. The second half of Book 30 is dominated by Valentinian I, emperor of the West. Ammianus presents a kaleidoscopic picture of this emperor alternating between admiration for his military qualities and devotion to his duty and bitter criticism of his avarice and cruelty. The account of his death forms the conclusion of Ammianus' treatment of the history of the western half of the Empire --