The war of 337-363 (which the author dubs the ‘Nisibis War’), was an exception to the traditional Roman reliance on a strategic offensive to bring about a decisive battle. Instead, the Emperor Constantius II adopted a defensive strategy and conducted a mobile defence based upon small frontier (limitanei) forces defending fortified cities, supported by limited counteroffensives by the Field Army of the East. These methods successfully checked Persian assaults for 24 years. However, when Julian became emperor his access to greater resources tempted him to abandon mobile defence in favour of a major invasion aimed at regime change in Persia. Although he reached the Persian capital, Ctesiphon, he failed to take it, was decisively defeated in battle and killed. The Romans subsequently resumed and refined the mobile defence, allowing the Eastern provinces to survive the fall of the Western Empire.

‘This is an interesting account of an important late Roman conflict, the last major clash between the Persians and the theoretically united Roman Empire, before the fall of the Western Empire. It demonstrates that even this close to the beginning of the end in the West, the Empire had a powerful army and under capable leaders was perfectly able to defend itself against attacks on multiple fronts.’ (History of War)

‘The Nisibis War offers us some excellent strategic analysis, helping explain the many military problems confronting the late empire, and evaluating the abilities of the respective armies and leaders, particularly the over-rated Julian, altogether providing us with a good account of a very confusing conflict, in an area still in contention.’ (Strategy Page)