This map shows the East-Elbian lands of the Duchy of Prussia in the eighteenth century. The term “East-Elbian” was not geographically limited to the territory east of the Elbe, but also included the Altmark, which lay west of the Elbe. What the East-Elbian lands had in common was that their flat landscape and fertile soil predestined them for agricultural use, which was dominated by large aristocratic landowners. Accordingly, the areas east of the Elbe gained enormous economic importance as a granary, which made them the main object of Prussian territorial expansion efforts, particularly under Frederick II.