Introduction ; Roman military organization. Legion ; Detachments ; Auxiliaries -- Weapons and equipment. Helmets ; Body armour ; Shields ; Shafted weapons ; Bladed weapons -- Command and control. Legion command ; Centuriate ; Junior officers ; Equestrian officers ; Command and control in action -- The Roman Army in battle. Roman tactical doctrine and practice ; Legion ; Auxiliaries -- Engineering. Marching and practice camps ; Forts and fortresses ; Siegeworks -- After Actium. Saltus Teutoburgiensis, a province lost ; Mancetter, a province saved Second Cremona, a throne won ; Mons Graupius, a battle too far -- Pax Romana -- Chronology. Roman emperors -- Ancient authors. Josephus (b. AD 37) ; Suetonius (b. c. AD 70) ; Tacitus (b. c. AD 56).