The expression “barbarian” has always represented a derogatory term, a sort of insult.
The Greeks called Barbarians those peoples who lived beyond their borders, who did not speak Greek, who did not share their culture, precisely in order to emphasize that incomprehensible babble through which the foreigners used to express themselves. The Romans considered barbarians all the peoples of the northwest who had Germanic or Celtic ancestry, who didn’t belong to the Roman political community, and who did not live in complex urban settlements, in cities. Instead, even if the provincials, the free subjects who lived in the provinces, were still far from the process of becoming “romans”, they weren’t seen as barbarians.
The barbarians were considered savages and primitive peoples and the word "barbarian" comes from their shabby grooming. The image we have today concerning these people comes from the portrait originated by the Roman historians, who disapproved them; however, many of them were able to seize in the barbarians’ word a potential that was missing in the classical civilization. This is not yet the case of Caesar, who described, like a very expert ethnographer and with a touch of admiration, the customs of the Gauls and Germans; Tacitus, instead, with his well-known piece "De origine et situ Germanorum", implicitly compared the nobility, the pride, the sense of independence, and the energy of the Germans with the qualities, too often opposite, of the Roman Empire. Towards the end of the Roman Empire, a strong distrust, a sense of fear towards the barbarians took over. They were seen as the antithesis of civilization, as destroyers, individuals from whom our "more advanced societies" must keep alert to prevent possible “relapses” into barbarism or savagery. This is the image of the wild warrior, with no rules, that continues up to today.
Modern historians have instead re-evaluated this period and its protagonists. Even if this age was characterized by invasions, destruction, and violence, the essential structures of the power remained intact; rather, those systems overlapped and integrated those of the winners’ peoples. For a long time, the Roman Empire survived thanks to troops provided by the barbarians, and many of the great generals, such as Aetius and Stilicho, were of barbarian origins. At the beginning, they fought like auxiliary troops under the command of a Roman officer, and then they passed directly under the banner of the eagle as allied or federated troops leading their own leaders. The armies of the last period were like those of enemies, both in clothing and in the armament.
On the ruins of the Roman Empire disintegration, Roman-barbarian empires were built, thanks to the Franks in France, the Vandals in Africa, the Ostrogoths in Italy, the Swabians and Visigoths in the Iberian Peninsula, the Saxons, and Germans and Thuringii in Germany, the Angles in England, just to name a few. These kingdoms were Romans from the educational, organizational, and administrational point of view, but the way they controlled and protected the land, their military and tribal divisions were barbarian. Throughout the Middle Ages, people continued to talk about barbarians, always to indicate, according to the Roman tradition, the people who did not belong to the sphere of common civilization.
At that time the distinguishing criterion changed, becoming the religious. Barbarians were then people not yet converted to Christianity: the Germanic, the Slavic, and Central Asian tribes. The term “barbarians”, which was not accepted by all theologians, (many of them, among which we can mention Thomas Aquinas, preferred the expression gentes or gentiles), has never been applied neither to the Jews, nor to the people from the Byzantine Empire. It was, instead, applied to Muslims; for example, when it came to talk about this population, the word “barbarian” rose derivatives such as "barbaresque" and sort of things like that.
The modern meaning of the word "barbarians" was created during the European Humanism; this term contains a strong negative value, and defines a real lack of civility, interpreted as repugnance to all the laws of a civilised life. At that time, the ideal re-evaluation of the Greek and Roman classical period, identified as the greatest historical moment for the civilization and culture blooming, brought automatically to identify everything was opposite to this model as barbarity, considered as the fundamental characteristic of those people who, as it was believed, had put an end to the greatness of the Roman Empire.