In the Middle Ages, the area of what was later to become Austria was a point of contact between the Mediterranean and northern alpine Europe. The border that ran from east to west between the Roman Empire and the “barbarians” shifted to become a frontier running north to south between the Frankish Christian empire and its initially heathen neighbours to the east. Gradually, linguistic borders developed between the Romance, Germanic, Slav and Steppe peoples. However, these borders were neither proto-national frontiers nor a bastion of western civilisation. It was here that cultures entered into contact in a wide range of political constellations. The volume focuses on the question of the development and importance of the eastern frontier of the Carolingian Empire. Reference is made to both historical and archaeological findings. In addition, the authors examine the extent to which the borders were perceptible. In order for clear borders to develop from a wide range of cultural differences, they had to be given particular significance by naming, description, narration or standardisation. Political and ethnic borders as a special form of social border require particular historical, emotional and transcendental justification. But these outlines, no matter how fantastic, had to prove their value in practical action. It was only from this combination of practice and significance that countries and peoples came into existence as large- area and super-temporal units.