A fully illustrated account of the great reform of the Roman Army from the time of Diocletian until the fall of the Western Roman Empire in 476 AD. After the 50-year chaos of the mid-3rd century AD, Emperor Diocletian (284–305 AD) and his successor, Constantine I (306–337 AD), the first Christian emperor, implemented significant administrative reforms to reflect the new realities and improve defensive strategies. These changes led to a complete reorganization of the Roman Army, with the old structure of legions and auxiliary units giving way to mobile field armies and various categories of guard troops. Furthermore, the army began recruiting "barbarian allies" in increasing numbers and even promoted some to higher command levels. Military analyst Raffaele D’Amato draws on the latest archaeological and written evidence to explore this turbulent final period of the Western Roman Empire. Illustrated with photographs and drawings of surviving objects and images, this final volume in a series documenting the evolution of the Roman Army also features eight new color depictions showing the uniforms and weapons of the reformed Roman forces.