The most important historical development of the fifth century in the West was the emergence of the Germanic kingdoms, which engulfed the former western provinces of the empire: The main groups were the Visigoths in southwest Gaul and Spain, the Burgundians in the upper Rhone valley, the Merovingian Franks of northern and central Gaul, and the eastern Goths, based in Pannonia through the third quarter of the century, who were to take control of Italy under Theoderic. In addition, the ethnic and political landscape included Suebians in northwest Spain; Saxons, who were active in the English Channel and on the European Atlantic seaboard; Thuringians and Scirians east of the Rhine and in the upper Danube basin; as well as robust relics of Roman provincial society in Gaul, such as the group that formed around Aegidius and Syagrius in the Soissons district; the old landed aristocracy of Provence, who produced a Roman emperor in the person of Avitus; and the shadowy Bagaudae, attested in the western areas of Brittany and in northern Spain, who may have been peasant insurgents, or the armed followers of regional landowners.
The major groupings, by organizing armed forces under recognized leaders, were able to assert their status as independent kingdoms, based on permanent occupation of territory within the former Roman dioceses of Gaul and Spain. The legitimacy of each kingdom depended not only on its innate political and military authority, but also on its relationship to the Roman emperors, from whom all claimed recognition. Institutionally, the fifth century kingdoms combined Germanic tribal practices with those of Roman provincial society. The most important of these was the retention, usually in modified form, of Roman legal practices, which were embodied in new written law codes. For the most part German kings ruled their subjects with Roman methods and tools. The populations of these kingdoms were mixed. The majority were evidently the indigenous Roman provincial inhabitants, of all classes and stations from the simplest peasants to the great landowners, who perforce recognized in the Germanic tribal kings a new set of authorities to replace their former Roman governors. The tribal rulers required land for themselves and their followers. The nature of this land settlement (see pp. 211–2) is both obscure and controversial, although it is fundamental to our understanding of how these kingdoms functioned in economic and social terms.
This revolutionary change to the political environment of the western provinces destabilized existing power structures. The urban centers, which had been the main focal points of Roman authority, declined, particularly in northern and central Gaul, and yielded ground to power based in rural landholdings. The tendency to retain wealth in the countryside rather than concentrate it in urban centers had always been an important aspect of Gallic society. Meanwhile, civic leadership at a local level was increasingly a matter for the church and its bishops. These played a leading role in championing their communities, intervening to protect local people from the newcomers, and mediating between the Roman and German peoples. Religion, however, remained a major means of differentiation between the Romans and most of the Germanic groups. The Christian Roman population of the western provinces had been almost universally Catholic and Trinitarian since the pioneering years of the mid-fourth century. The Germanic tribal peoples were mostly Arian. Religious polarization, while rarely a source of overt friction (as it was in Vandal Africa), remained nevertheless a crucial strategy which helped to perpetuate the distinction between the old and new populations (see p. 319). Religious allegiance also helped to define the stance of specific Germanic groups to the Roman Empire. Thus when the Frankish king Clovis adopted Christianity towards the end of the fifth century he was baptized a Catholic by bishop Remigius of Reims (see pp. 227–8). This aligned him as a potential ally of the eastern Roman emperors and marked his opposition to the Arian Visigoths. In like manner the majority of the Burgundians declared themselves to be Catholic as part of their strategy to align themselves as far as possible with Roman interests during their power struggles with their neighbors.