The book examines the stages of development of the late Roman military system... Its formation, which lasted more than half a century and was completed during the reign of Emperor Constantine I (306–337) and his sons; its modifications, which continued until the reign of Theodosius I, as a result of which the army acquired the ability not only to fight any enemy on equal terms, but also to defeat him; the rapid and irreversible barbarization of the army is the most striking sign of the impending degradation and decline of the late Roman military system. For specialists in ancient history and military affairs of antiquity and all those interested in the history of Ancient Rome.