When the Allied invasion of Southern France took place, Army Group G had eleven divisions with which to hold France south of the Loire. Between August 17 and 18, the German Armed Forces High Command ordered Army Group G (with the exception of the troops holding the fortress ports) to abandon southern France. The German LXIV Corps, which had been in charge of troops in the southwest since First Army had been withdrawn a few weeks earlier to hold the line on the River Seine southeast of Paris, formed three march groups and withdrew eastward toward Dijon. At the same time, the German Nineteenth Army, retreated northward through the Rhône valley toward the Plateau de Langres where it was joined by the German Fifth Panzer Army which was assigned to Army Group G so that a counter-attack could be delivered against the United States Third Army. The retreat did not go according to plan, as the Nineteenth Army retreated many personnel of Army Group G were taken prisoner by the Sixth United States Army Group. By the time the retreat was over General Johannes Blaskowitz had lost about half his force and was relieved on 21 September by General Hermann Balck. By mid September the Fifth were in position on the left wing of the German line north of the Swiss border. From there the Fifth Panzer with elements of the First attacked the United States Third Army, while the much reduced German 19th Army opposed the French First Army and the U.S. Seventh Army under General Alexander M. Patch.