Map showing the German Eastward Expansion, starting in the early Middle Ages at the zenith of Charlemagne’s Frankish Empire. Although first German settlements east of the river Elbe in modern Eastern Germany started relatively early, it wasn’t until the 10th and 11th centuries, that larger amounts of Germans moved eastward and assimilated most of the Slavs that had settled there during the migration period. The Sorbs, a Slavic minority in eastern Germany, are an exception surviving to this day. The expansion was later on accelerated by the Northern Crusades of the Teutonic Order, culminating in the subjugation of the Old Prussian and the founding of the German duchy of Prussia.