For centuries, scholars have grappled with a fundamental contradiction in Ptolemy’s Geographike Hyphegesis. Traditional interpretations identify the Asciburgius Mons with the Giant Mountains (Krkonoše) and the Vistula River with the modern river flowing through Poland. Yet this classical identification creates a serious hydrographic impossibility: according to Ptolemy’s own coordinates, the majority of the river’s course — including its main sources — would have to lie far south of the Giant Mountains, deep in central Bohemia. Such a configuration contradicts the actual topography of the region and has long remained one of the most puzzling inconsistencies in ancient geography. Sven Mildner’s groundbreaking geodynamic reinterpretation offers a convincing resolution by proposing that the Asciburgius Mons is not the towering Giant Mountains at all, but rather the more modest Fläming range in eastern Germany. This new identification elegantly dissolves the paradox and relocates the ancient Vistula and its southern sources to the river systems of the Schwarze Elster, Spree, and Oder in the Lausitz region — where the topology finally makes coherent geographical sense.