The Rhine is one of the longest rivers of Europe (1320 km). This river, Rhenus in Roman, became the frontier of the Roman Empire after 260 AD, when German tribes crushed and crossed the frontier on the right side of the Rhine, called Germania Superior. The other part of occupied German territory was called Raetia, the territory on both sides of the Danube. The Romans occupied a large territory on the right bank of the Rhine since the last quarter of the first century AD and built many castles and fortifications in order to protect this frontier area. This frontier, the Limes, has been recognized as World Heritage by UNESCO. There were actually two Limes in Germania Superior: the Rhine (during the first century and after 260 AD) and the territory on the right bank of the Rhine from 100-260 AD.
Many Roman settlements on the right bank survived the fall of the Roman Empire in the fifth century and became big cities in the centuries to come (Frankfurt, Karlsruhe, Stuttgart, Heilbronn for example). Many settlements and strongholds on the left bank of the Rhine became important medieval towns (Koblenz, Strasbourg, Speyer, Basel, Worms, Mainz, Bonn and Cologne). The Rhine has always been the most important waterway and trading route of southern and northern Europe, connecting the Mediterranean and the North Sea.
The golden age of the Middle Rhine Valley, a gorge of 65 kilometers between Rüdersheim and Koblenz, with its Roman (and Celtic) roots started in the eleventh century and it should take the Thirty Years War (1618-1648) , the War of the Palatine Succession (1688-1697) and finally the French revolutionary armies and Napoleonic Wars (1792-1813) to put an end to the independent military and political powers on both banks of the Rhine.
The valley is a gorge with many prosperous towns and settlements of Roman and medieval origin and about 40 medieval castles on the heights overlook the river. Most castles were built between the eleventh and fourteenth centuries, when this region was part of the Holy Roman Empire. Many local lords, the powerful bishoprics of Trier, Mainz, Cologne and their prince-electors, the counts Palatine, abbeys and convents competed to control the Rhine and its lucrative toll system. The region was a patchwork of sovereign political entities and military confrontations were the rule. The end of this patchwork and the formation of two big nation states, France and Germany, did not alter the belligerent mood after 1871 however. On the contrary, the worst had still to come.
By this time the castles of the Middle Rhine Valley were in ruins and devastated, only the Marksburg castle, north of Boppard, has never been destroyed since its foundation in 1219. It is the irony of history that this destruction gave rise to the (touristic) boom in the course of the nineteenth century however. One reason was politically motivated. The Middle Rhine Valley was ceded to the Kingdom of Prussia at the Congress of Vienna in 1814 and 1815 and the Prussian kings and aristocracy legitimised their new possessions by rebuilding the medieval castles and fortifications. The other reason was the Romantic period and the beginning of tourism, mainly by British en route on their Grand Tour and by the fast growing German middle class. The industrialisation and the increasing economic relevance of the Rhine gave a boost to the often impoverished cities and towns as well.
Although it seems highly unlikely that the Rhine will be at the centre of any military dispute between neighbouring countries in the (near) future, the castles and fortifications are a warning from history, innocent as they may look like today. The Middle Rhine Valley is not just a beautiful region, it has a story to tell. (Source: A. Pecht, Upper Middle Rhine Valley, Regensburg 2014).