When Eisenhower was appointed Supreme Allied Commander for the planned Normandy landings he suggested that Alexander become ground forces commander, as he was popular with both British and American officers. Bradley, who after Normandy commanded the U.S. 12th Army Group, remarked that he would have preferred to work with Alexander, rather than Montgomery, as he regarded the former as "a restrained, self-effacive and punctilious soldier". Of the problems that subsequently surfaced with Montgomery's command of the Anglo-Canadian 21st Army Group, Bradley suspected they would not have occurred with Alexander in command. Brooke, however, applied pressure to keep Alexander in Italy, considering him unfit for the assignment in France. Thus, Alexander remained in command of the 15th Army Group, and, with the support of numerous Allied commanders, controversially authorised the bombing of the historic abbey at Monte Cassino, which resulted in little advance on the German Winter Line defences. It was not until the fourth attempt that the Winter Line was breached by the Allies, and Alexander's forces moved on to capture Rome in June 1944, thereby achieving one of the strategic goals of the Italian Campaign. However, the U.S. VI Corps in the Anzio beachhead, under Clark's orders, failed to follow their original break-out plan that would have trapped the German 10th Army escaping northwards in the aftermath of the Battle of Monte Cassino, instead favouring an early and highly publicised entry into Rome two days before the Allied landings in Normandy.