The reconfiguration of the empire
By the end of the 5th century, however, most of the non-Roman peoples settled in the West were adopting Roman customs and Christian belief. Intermarriage with established Roman families, the assumption of imperial titles, and, finally, conversion assisted a process of acculturation among their leaders, for instance, in the case of Clovis, the Frank. Theodoric the Ostrogoth established an impressive “sub-Roman” kingdom based on Ravenna, where public buildings and churches served by an Arian clergy competed with imperial monuments. Increased Roman influence can also be seen in the law codes promulgated by the Visigoths Euric (late 5th century) and Alaric II (the Breviary of 506) and the Burgundians, Bavarians, Ostrogoths, and Franks (Lex Salica, 507–511). Christianity often provided the medium for incorporation into old imperial structures. While the Goths were still in the Danube basin, they had embraced Arian Christianity (which denied that the Son was of the same substance as the Father), and their first bishop, Ulfilas, translated the Bible into Gothic. Given its heretical nature, this religious literature in a written vernacular could not survive, and, with conversion to orthodox (“catholic”) Christianity, the barbarian languages gradually gave way to Latin.
Nonetheless, the Germanic tribes brought into Europe their own tribal institutions, ethnic patterns, and oral and artistic traditions, including a highly developed epic poetry. Their influence was strongest in central Europe, where the Romans had had the least impact; less marked in the northern and eastern parts, where Romano-British and Gallo-Roman cultures were established; and weakest in the highly Romanized southern regions. Linguistically, Old High German developed in the first zone and Anglo-Saxon in Britain, while farther south medieval Romance languages developed from their common Latin inheritance.
In the southern zone, imperial traditions were reinforced by the reconquest, albeit brief, of North Africa, Italy, and parts of Spain by forces from Constantinople under Justinian’s general Belisarius. Despite the restoration of Roman administration between 533 and 554 (celebrated in the mosaics of Ravenna and the Pragmatic Sanction of 554), imperial forces could not prevent the Lombards from moving inexorably into northern Italy, which they occupied in 568. The reconquered parts of the Western Empire were thus reduced to a narrow strip of territory from the head of the Adriatic to Ravenna, the exarchate, Rome—now governed effectively by its bishop—plus small duchies. In addition, Sicily, Bruttium, and Calabria remained subject to Constantinople and were Greek-speaking for many centuries.
In contrast to previous invaders, from the 6th century onward, newly arrived barbarian forces clung to their pagan culture and resisted assimilation. The Saxons established themselves east of the Rhine in the north. The Avars and their Slav allies, who moved steadily westward from the Vistula and Dnepr river basins, disrupted weak imperial defenses at the Danube and pressed south and west into the Balkans and central Europe. By 567 the Avars established control over the Hungarian plain, where they remained until their defeat by Charlemagne in 796. After successfully besieging Sirmium and Singidunum in the 580s, the eastern Slavs infiltrated the Balkans, while others moved north and west to settle eventually along the Elbe beside the Saxons. The failure of the combined Avaro-Slav siege of Constantinople in 626 ended this pagan expansion. Although Slavs occupied the Balkan Peninsula for two centuries or more, disrupting east-west communication along the ancient Via Egnatia, they were eventually evangelized and absorbed into the Eastern Empire.