Whether or not it's true that Charlemagne himself brought winemaking to the eastern bank of the Rhine River, the historical record shows that the eastward expansion of viticulture in Germany is roughly contemporaneous with the era of Charlemagne and the spread of Christianity. More importantly for present-day enthusiasts of German wines, the Rhine region is reportedly the site of the first Riesling plantings, near the Rheingau in 1435. Seven centuries later, the Riesling grape has a near-monopoly on the most favorable growing sites, not just in the Rhine, but in all of Germany.