The auxiliary regiments of the Imperial Roman army were as vital to the defensive and offensive capabilities of the Roman Empire as the better-known Roman legions. Initially raised on an ethnic basis through the levy from among Rome 's subject peoples, and then maintained at or near their full strength by conscription and voluntary recruitment, these units of auxilia were often deployed far from their original ' home As such, by analysing where these units were recruited and in what numbers, and then studying their subsequent history and deployment, it is possible to begin an assessment of their full value to Rome and to better comprehend overall developments in Roman strategic thinking. This paper contributes to such an appraisal by reviewing the evidence for the history and deployment of the three cohortes Augustae Cyrenaicae, among the least well-known auxiliary units in the entire Roman army.