Ninth Army
During the crisis of the Battle of the Bulge, the Ninth Army came under Montgomery's command on December 20. The Ninth Army took no part in the battle, but was stripped of eight divisions to reinforce the First Army, and took over part of its front. After the battle was over in early 1945, the Ninth Army remained with Montgomery's 21st Army Group for the final attack into Germany. For Operation Grenade, the crossing of the Roer, the Ninth Army was reinforced, its strength increased from five to twelve divisions. The major obstacle to the advance was the river itself, as the dams were still in German hands.