During the first week of the Normandy landings and the Battle of Normandy, Bradley's First US Army formed the right wing of the Allied lines. They were joined during July by the Third US Army, under the command of General George S. Patton, to form the Twelfth Army Group. Twelfth Army Group became operational in France on 1 August 1944. With General Omar Bradley assuming command of the Twelfth Army Group, Lieutenant General Courtney Hodges assumed command of the First Army.