This ambitious series gives the reader a comprehensive narrative of late Roman military history from 284-641. Each volume gives a detailed account of the changes in organization, equipment, strategy and tactics among both the Roman forces and her enemies in the relevant period, while also giving a detailed but accessible account of the campaigns and battles. This volume covers the period from Julian's accession as sole Emperor in 361 to the permanent division of the Empire into East and West on death of Theodosius I. It therefore encompasses significant defeats for Rome against very different enemies: Julian's expedition against the Sassanid Persians and Valen's defeat by the Goths at Adrianople, both emperors being killed. Full attention is paid to all the campaigns of this critical period, illustrating the varied threats which put immense pressure on all the Empire's frontiers and the varying success of the Roman responses.