The Roman imperial army was one of the main factors of political control exercised by the emperors. Effective political management of the army was necessary to maintain the overall security and prosperity of the empire. This book analyzes the means by which the emperors controlled their soldiers and maintained their loyalty from the Battle of Actium in 31 BC to the fall of the Severan dynasty in 235 AD.

Recent discoveries have revolutionized our understanding of the Roman army. This study provides an informed synthesis of a range of evidence from archaeological, epigraphic, literary, and numismatic sources regarding the emperor's relationship with his soldiers. It demonstrates that this relationship was intensely personal. The emperor was not only their commander-in-chief but also their protector and benefactor, even after their retirement. However, army management was more complex than this emperor-soldier relationship.

An effective army requires an appropriate military hierarchy to enforce discipline and guide the troops daily. This was particularly significant for the imperial army, which was mainly dispersed along the empire's borders, essentially forming a series of distinct armies. The emperor had to ensure the loyalty of his officers by building mutually beneficial relationships with them. In this way, the imperial army became a complex network of interconnected loyalty ties that protected the emperor from military subversion.