Alexander remained in command of the 15th Army Group, as well as its successor, the Allied Armies in Italy (AAI), for most of the Italian Campaign, until December 1944, when he relinquished his command to Clark and took over as the Supreme Commander of the Allied Forces Headquarters, responsible for all military operations in the Mediterranean Theatre. Alexander was concurrently promoted to the rank of field marshal, though this was backdated to the fall of Rome on 4 June 1944, so that Alexander would once again be senior to Montgomery, who had himself been made a field marshal on 1 September 1944, after the end of the Battle of Normandy. Alexander then received the German surrender in Italy, on 29 April 1945. Further, as a reward for his leadership in North Africa and Italy, Alexander, along with a number of other prominent British Second World War military leaders, was elevated to the peerage on 1 March 1946 by King George VI; he was created Viscount Alexander of Tunis and Errigal in the County of Donegal.