Theater of Operations, United States Army (SOS NATOUSA), commanded by Major General Thomas B. Larkin, which was responsible for the logistical support of U.S. Army forces in the Mediterranean. British General Sir Harold Alexander became commander of the British 18th Army Group, which was activated on 19 February 1943, and was responsible for the detailed planning and preparation, and the actual conduct, of combat operations. In effect, Alexander was the ground commander. Air forces were grouped under the Mediterranean Air Command under Air Chief Marshal Sir Arthur Tedder, which became active the day before. This included the US Ninth and Twelfth Air Forces. For the Allied invasion of Sicily, Alexander was appointed Eisenhower's deputy commander in chief and responsible for ground warfare, while Cunningham and Tedder remained the naval and air commanders respectively. Having overseen the early stages of the Italian Campaign, Eisenhower left AFHQ on 8 January 1944 and returned to England to assume command of the forces assembling for Operation Overlord, codename for the Allied landings in Northwest Europe. He was succeeded as Supreme Allied Commander in the Mediterranean by British General Sir Henry Maitland Wilson. Lieutenant General Jacob L. Devers became Wilson's Deputy Supreme Commander and also the commanding general of NATOUSA. Operation Dragoon, the Allied landings in Southern France, was conducted by the Mediterranean Theater. An advance echelon of SOS NATOUSA was organized in Italy and arrived at Dijon on 12 September to control the Delta Base Section and Continental Advance Section (CONAD). SOS NATOUSA became Communications Zone (COMZONE) NATOUSA on 1 October, Lieutenant General Joseph T. McNarney succeeded Devers as the Deputy Commander of NATOUSA on 22 October, allowing Devers to devote all his time and energy to running the 6th Army Group in France. The 6th Army Group was activated on 1 August, and it became operational in France on 15 September. NATOUSA was redesignated Mediterranean Theater of Operations, United States Army (MTOUSA), on 1 November 1944, and no longer had any responsibilities in Southern France. MTOUSA boundaries were considerably diminished (on the north) from those of NATOUSA, and U.S. Army forces in southern France passed to the administrative control of ETOUSA. The forces in Southern France had their own line of communications from MTOUSA, but by February 1945 the integration of the Southern Line of Communications (SOLOC) with ETO Communications Zone had progressed to the point where the SOLOC headquarters was superfluous, and