Legio III Italica: one of the Roman legions. Its name means "the Italian legion".
Together with II Italica, this unit was founded in 165 or 166 by the emperor Marcus Aurelius, who needed extra soldiers in his war against the Germanic Marcomanni.note[Cassius Dio, Roman Histories 55.24.4.] The Third was to operate on the western front, i.e., the Upper Danube. Probably from the very beginning, the legion was surnamed Concors, "harmonious", which makes sense: Marcus Aurelius had a co-emperor, Lucius Verus, and it may have been necessary to stress that the two men were living in harmony. The name Italica suggests that the recruits were from Italy, and indeed, an inscription shows that at least one of them was born at Como,
It is likely that the legion was, together with I Adiutrix and II Italica, part of a task force commanded by Publius Helvius Pertinax, the future emperor. This army group had to secure Raetia and Noricum, provinces threatened by the Marcomanni. It is unclear where the legion was stationed in the first years of its existence, although we know that a subunit made up from soldiers of II and III Italica was on duty at Salonae (modern Split) in Dalmatia.
After 171, the presence of the Third is attested in Raetia near the ancient Celtic settlement Radaspona, where the soldiers built Regina Castra, "Castle on the river Regen", or Regensburg. It was a strange construction. Like all Roman legionary bases it had a gridiron lay-out; but it was a real castle, with giant walls. They are 8 meters high and 2 meters wide. Other camps were more "open", as if the legions could march out any time. Regensburg, however, is essentially a defensive construction of a type that became popular in the early fourth century. A building inscription can be dated to the year 179, shortly before the death of Marcus Aurelius.
The soldiers were also active in other towns in Raetia, for example in the provincial capital at Augusta Vindelicum (modern Augsburg), which was not far from Regensburg. This comes as no surprise, because the commander of the legion usually also served as governor of Raetia. Legionary officers and soldiers were often employed in the provincial bureaucracy. Other inscriptions show that the soldiers were active in smaller towns as well.
A bronze tablet, containing a dedication to the mountain god Poenus by the legion's quartermaster, has been discovered in the Great St.Bernard pass. Although it is very tempting to assume that it has something to do with the food supply of the army of the Danube, this is not possible, because we know of the existence of a forager's office at Trento, close to the Brenner pass. A man of equestrian rank was responsible for this office.
On 1 January 193, the old general Pertinax became emperor, but he was killed after a very brief reign. A rich senator, Didius Julianus, became ruler of the Roman empire. Immediately, the governor of Pannonia Superior, Lucius Septimius Severus, proclaimed himself emperor. III Italica was among the legions that recognized him, and joined his march on Rome. Later, subunits of the legion were employed during Severus' campaigns against his rivals Pescennius Niger and Clodius Albinus, and perhaps during his wars against the Parthian empire.
Severus' son Caracalla employed the third Italian legion, together with VIII Augusta and XXII Primigenia, during his successful campaign against the Alamanni in 213. That (a subunit of) III Italica was also present during the same emperor's expedition against the Parthians, can not be proven, but is very likely. The tombstone of Paulus from the reign of Caracalla from Perinthus in Thrace (below) mentions a soldier of our unit, and it is hard to find a better explanation for his presence in the east.
An inscription calling the legion III Italica Gordiana shows that (subunits of) the legion joined a campaign during the reign of Gordian III. This can only refer to the expedition against the Sassanid Persians in 243-244.
During the third century, the legion played its part during the throne struggle. In 253, Valerian was proclaimed emperor by the army of the Danube and III Italica must have been involved. It was now officially surnamed Pia fidelis ("faithful and loyal"). During the conflict between the emperor Gallienus and his rival Postumus, the legion supported the first-mentioned, for which it was rewarded with surnames like Pia VI Fidelis VI ("six times faithful and loyal") and Pia VII Fidelis VII.
By that time, it was still based at Regensburg on the Danube and could send subunits to other parts of the empire. We know that soldiers of III Italica fought against queen Zenobia of Palmyra in a campaign conducted by the emperor Aurelian in 273.
The legion still existed at the end of the fourth century, although it was now divided into six smaller units. Five of them guarded the river fords against the Alamanni and Ostrogoths, and must have done so until the Danube frontier collapsed in third quarter of the fifth century. (Regensburg was occupied by the Bavarians.) The sixth unit had been transferred to Illyricum, where it is mentioned as the twin of III Herculia.
The emblem of the third Italian legion was the stork.
K. Dietz, "Legio III Italica", in: Yann Le Bohec, Les légions de Rome sous le Haut-Empire (2000 Lyon) 133-143