The centuries between A.D. 400 and 800, which make the transition between Antiquity and the Middle Ages, are sparsely documented and have often been called by the English the ‘Dark Ages’, the dark centuries of Western European history. This paucity of written historical sources is greatly to be regretted, for these were decisive centuries for the formation of European society and in them occurred events whose results are to be seen even to the present day. The Roman Empire with its ancient civilisation collapsed; the countries on the southern shore of the Mediterranean went over to Islam; the Slavs settled in the Balkans, North-Central Europe, and the territory around the Danube as far as Austria; and these Danube-lands came under the domination of the Mongolian Avars.
Quantitative reconstructions of changes in regional openness in north-central Europe reveal new insights into old questions