Legio III Augusta (“Third Augustan Legion”) was a legion of the Imperial Roman army. Its origin may have been the Republican 3rd Legion which served the general Pompey during his civil war against Gaius Julius Caesar (49–45 BC). It supported the general Octavian (later emperor Augustus) in his civil war against Mark Antony (31–30 BC). It was officially refounded in 30 BC, when Octavian achieved sole mastery of the Roman empire. In that year, it was deployed in the Roman province of Africa, where it remained until at least the late 4th century AD.
The Legio III Augusta was placed in Africa to ensure a steady grain supply to Rome. Under Augustus, the African Proconsul had command over it and several other legions. By the end of Tiberius’s reign, it was the only legion in Africa. Under Caligula, command of the army was withdrawn from the proconsul and given to a Propraetorial legate who answered directly to the emperor. The Legio III Augusta first set up camp at Haidra before 14. The base at Haidra was not large enough to support an entire legion; this suggests that the legion was split up. Desert warfare required a small and highly mobile fighting force and it was not unheard of for the emperor to split a legion into several vexillations and place them at separate fortresses. For the most part, whole legions were not moved into Africa but rather, small vexillations were formed from the armies of Germany and Pannonia and sent to help when needed.
The Roman military presence in North Africa was not always accepted or welcomed. Most notably in opposition to the Roman institution was Tacfarinas, a former Roman soldier turned Musulamii guerrilla leader. Tacfarinas is an example of the multiple rebellions against the expansion of the Roman Empire through military establishment and geographical positioning as well as the adequate and tactful response by the Third Augustan Legion.
Tacfarinas attacked the Augustan Legion when they were particularly vulnerable. It is reported that the first attacks were in 14 BC when the Legion had just completed its first building project. The timing suggests that the Third Augustan Legion had not yet established its roots or an approving reputation. The guerrilla warfare tactics combined with Tacfarinas’ novel approach to attack from the rear, created additional difficulties for the Third Augustan Legion in their efforts to defeat Tacfarinas.
The manner in which Tacfarinas led his rebellions was of particular concern to the Third Augustan Legion. At first, Tacfarinas did not appear to be a great threat; his initial band of fighters was composed mainly of robbers and rebels. However, Tacfarinas’ band of robbers soon gained the expertise and precision of the Roman Army. Tacfarinas traveled through North Africa collecting Roman soldiers left behind by the Third Augustan Legion; Tacitus describes this process as a “cherry picking ” of sorts, using soldiers who had already been trained by the Roman army and using their skills against their creator. Tacfarinas created a new coalition from the collected Roman soldiers and North African citizens looking to rebel against the expansion of the Roman Empire into the Musulamii people, under his sole command.
With the traditional tactics used by the Roman army, the enemy was expected to attack in formation, as the Roman legions did. With the rebellion of Tacfarinas, Roman commanders had to change their mode of attack. The general of the Third Augustan Legion split up the army into small units of men that took orders from a commanding officer. These units of men were constantly battle ready, mobile, and trained to fight in the desert, anticipating attacks from Tacfarinas and his rebels. With this change in traditional tactics, Tacfarinas was defeated in a matter of years.
Tacfarinas’ army was ultimately defeated and Tacfarinas himself committed suicide, however his revolts and rebellious efforts should not go unnoticed. The Third Augustan Legion had to master the revolutionary techniques of Tacfarinas’ band of robbers and ex-soldiers to succeed in conquering Tacfarinas. The guerrilla warfare strategies that Tacfarinas displays are one of the many ways the Third Augustan Legion had to alter its defense techniques in order to settle rebels throughout North Africa. The Musulamii gang under leadership and control of Tacfarinas was just one example of rebellions that the Legion had to settle, however no army of rebels proved as difficult, incessant, or resilient as the guerrilla army under Tacfarinas.
The Third Augustan Legion was responsible for multiple building projects and the enforced the presence of the Roman Empire against rebellions in North Africa for over three hundred years. However, they influenced the frontier in ways other than through expansion and urbanization. Militarily, they reformed the structure of the frontier through cultural changes and their mere presence throughout Africa.
However, the legion was self-sufficient in protecting the African provinces for the majority of the time. Most threats that required reinforcements arose in Mauretania, as this was where the Moors were the most dangerous. The Third Augustan had around 5000–6000 men with about 10,000–15,000 auxiliary men stationed close by. Almost half of these soldiers were stationed in Mauretania Tingitana; the rest were positioned based on the military needs of that time. The Emperor Vespasian reunited the legion in a single fortress at Theveste, most likely in 75. In 115 or 120, the Legio III Augusta established their camp at Lambaesis where it remained for two centuries apart from the period 238–253.
The legion was disbanded in 238 AD “because of its role in putting down an African-based revolt against the emperor Maximinus in favor of the provincial governor Gordianus.”Capelianus was a legate in the legion and the officer who (mis)used his legion to attack Gordian. For this reason, Gordian III disbanded the legion.
In 252, Valerian reformed the legion to deal with the “five people groups”, a dangerous coalition of Berber tribes. The legion prevailed in 260 but the threat remained, and fortifications of Lambaesis were expanded over the following years. In 289, the struggle began again and the emperor Maximianus took personal control of the legion. The war lasted until 297 at which point the legion was victorious.
In the early 4th century, Diocletian personally put down a rebellious governor and immediately afterward, transferred the Legio III Augusta from Lambaesis to another, unknown base within the region. Diocletian often worked with the legion during the period of military anarchy from 235 to 284. He was particularly prolific with his building projects, many of which were in Africa. Most of the projects were aimed at either replacing earlier works destroyed during the period of military anarchy or repairing public improvements, which had been allowed to fall into decay. The Legion was the main labor resource for these projects. The legion was still mentioned as late as the early 5th century but the actual date of its final disbandment is unknown.