History of the Ruhr History of the Ruhr The actual boundaries of the Ruhr vary slightly depending on the source, but a good working definition is to define the Lippe and Ruhr as its northern and southern boundaries respectively, the Rhine as its western boundary, and the town of Hamm as the eastern limit. In the Middle Ages, local power was vested primarily in the counts ("Grafen") of Berg, Mark and Cleves. The left bank of the Rhine was held by the Archbishop of Cologne. The Hellweg was an important trade route crossing the region from Duisburg to Dortmund and beyond as far as
Battle of the Ruhr the Ruhr, Bomber Command estimated about 70% of their aircraft losses were due to fighters. By July 1943, the German night fighter force totalled 550. Through the summer of 1943, the Germans increased the ground-based anti-aircraft defences in the Ruhr Area; by July 1943 there were more than 1,000 large flak guns (88 mm caliber guns or greater) and 1,500 lighter guns (chiefly 20 mm and 37 mm calibre). This was about one-third of all anti-aircraft guns in Germany. Six-hundred thousand personnel were required to man the AA defences of Germany. The British crews called the area sarcastically "Happy Valley"