Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Pages: 102. Chapters: Roman legion, Imperial Roman army, Late Roman army, Roman infantry tactics, Auxiliaries, Roman army of the mid-Republic, Structural history of the Roman military, Alpine regiments of the Roman army, Early Roman army, Prorogatio, List of Roman auxiliary regiments, Roman command structure during First Mithridatic War, Laeti, Roman shipyard of Stifone, Roman military frontiers and fortifications, Alpinorum auxiliary regiments, Hippika gymnasia, Strategy of the Roman military, Limes Tripolitanus, Roman auxiliaries in Britain, Economics of the Roman army, Roman military tombstones, Cohors IV Aquitanorum equitata c.R., Cohors I Raetorum equitata, Cohors I Alpinorum equitata, Cohors III Aquitanorum equitata c.R., Cohors I Aquitanorum, Cohors I Alpinorum peditata, Cohors I Aquitanorum veterana, Cohors II Aquitanorum equitata c.R., Profectio, Cohors IV Gallorum equitata, Cohors III Alpinorum equitata, Cohors II Gallorum veterana equitata, Cohors II Alpinorum equitata, Marian Roman army, Cohors II Gallorum Dacica equitata, Aklys, Formula togatorum, Adlocutio, Adventus, Signaculum. Excerpt: The Imperial Roman army refers to the armed forces deployed by the Roman Empire during the Principate era (30 BC - AD 284). Under the founder-emperor Augustus (ruled 30 BC - AD 14 ), the legions, which were formations numbering about 5,000 heavy infantry recruited from Roman citizens only, were transformed from a mixed conscript and volunteer corps serving an average of 10 years, to all-volunteer units of long-term professionals serving a standard 25-year term. (Conscription was only decreed in emergencies.) In the later 1st century, the size of a legion's First Cohort was doubled, increasing the strength of a legion to about 5,500. To complement the legions, Augustus established the auxilia, a regular corps of similar numbers to the legio...