After almost two months of bloody and desperate fighting, the Allies had failed to break through the German defenses that had been limiting their hold on Normandy since D-Day. On July 25, 1944, the situation changed when the American Army launched Operation Cobra. With surprising suddenness, the VII Corps of the U.S. First Army smashed through the German line along the Periers-St. Lo highway. The breakthrough quickly widened as the VIII Corps liberated Avranches on July 31. The following day, the U.S. Third Army under the command of Lt. Gen. George S. Patton swept into the Brittany peninsula and southern Normandy. The breakthrough had quickly turned into a breakout.
A Canadian Offense Toward Falaise
Since the landings in early June, the British and Canadian forces to the left of the Americans had been fighting and pinning down the bulk of the German panzer divisions in Normandy. With the breakout of the American forces, the Germans had trouble finding reinforcements and began shifting away troops that had been facing the British and Canadians. On July 30, the British launched Operation Bluecoat on the American left flank, moving toward Vire and Mount Pincon. General Sir Bernard Montgomery, operational commander of Allied forces in Normandy, believed that the Germans would have to pivot their lines eastward due to the American breakout and that the British needed to do all they could to support the operations of the American forces west of St. Lo.