The effect of barbarians on the Late Roman army is a large and complicated topic. To begin with, it is important to understand that the popular conceptualization of the Late army, that of a fighting force that became “barbarized” and increasingly ineffective has been thoroughly rejected by modern scholars. Rather, the current consensus is that the army remained a quality institution. As I have mentioned before, although his methodology here is a bit problematic, Hugh Elton has estimated that only about a third of recruits for the field armies were drawn from peoples born outside the Empire. The attractiveness of military service in Late Antiquity is debated (so how many domestic recruits volunteered for service versus being involuntarily conscripted is questionable), but regardless of method, the remaining two thirds of recruits were drawn from inside the Empire. Also, barbarians (whom can be defined as individuals born beyond the frontier who likely did not identify as Roman) were not evenly spread throughout the army, but rather were concentrated in specific units (such as regular foederati regiments and, likely initially, many units of auxilia palatina). Roman-born recruits thus outnumbered non-Roman born recruits roughly two to one. It must also be remembered that the recruitment of barbarians was not a new practice, but rather dated back to the time of Caesar, and likely before. The army thus had a long history of successfully integrating barbarians into the army, demonstrated also by the army heavily recruiting and successfully integrating men from more rural, peripheral, and less “Romanized” areas of the Empire, such as Illyria and Pannonia.

Once recruited into the army, barbarians quickly came to identify with their units and comrades. All recruits, especially those in the field armies, were largely cut off from their families and home communities, but barbarians even more so. The contubernium and the emphasis training placed upon maintaining cohesion would have fostered unit identity, as would regimental standards and shield blazons. Loyalty to the emperor was also a constant theme. Upon completion of training, all recruits swore an oath of personal loyalty to the emperor, which was reaffirmed annually by the entire unit. Troops were paid special bonuses (known as donatives) upon the ascension of a new emperor and every five years thereafter; the coins used to pay donatives stamped with the emperor’s likeness. Loyalty to unit and emperor fostered a common identity for all recruits, regardless of their place of birth. Barbarians thus would quickly have come to identify strongly with their unit, and came to adapt a Roman cultural outlook. Upon retirement, it is likely most barbarian troops remained in the Empire, if for no other reason than after around twenty years of service, they would have had little remaining attachment to their home communities.

There is thus little evidence to support the assertion that the recruitment of non-Romans into the army had any demonstrable mal-effect on it’s performance. So long as the logistical network was sound, the Roman state remained able to field a well trained, well-equipped, and well-motivated fighting force. This is demonstrated in no small part by the army continuing to win the bulk of it’s field engagements throughout Late Antiquity. The army did undergo much change during the late third/early fourth century, and while the impetus for these changes is unclear, large-scale recruitment of barbarians was not a factor. That said, many barbarian customs were emulated by the army, especially among elite troops like the Scholae. These included the wearing of gold torques, beards, longer hair, and the barritus war-chant. However, it is difficult to make a connection between cultural emulation and poor combat performance.