Supreme Headquarters Allied Powers Europe of "Général d'Armée" Alphonse Juin, French Army. "Holdfast" was a major allied air-ground exercise involving 150,000 British Army of the Rhine, Dutch, Belgian and Canadian troops of NATO's Northern Army Group in coordination with the Allied Air Forces Central Europe. They maneuvered east of the Rhine River in the British Zone under the overall command of Lt. General Sir Richard Nelson Gale, British Army. Finally, "Rosebud" involved ground maneuvers by the U.S. Seventh Army in the American Zone of Occupation of Allied-occupied Germany. The initial plans saw the defence of Western Europe from a Soviet invasion resting heavily on nuclear
Supreme Headquarters Allied Expeditionary Force to this day. Southwick House was used as an alternative headquarters near Portsmouth. Its staff took the outline plan for Operation Overlord created by Lieutenant General Sir Frederick E. Morgan, Chief of Staff to the Supreme Allied Commander (Designate) (COSSAC), and Major General Ray Barker. Morgan, who had been appointed chief of staff to the Supreme Allied Commander (designate) in mid-March 1943 began planning for the invasion of Europe before Eisenhower's appointment. and moulded the plan into the final version, which was executed on 6 June 1944. That process was shaped by Eisenhower and the land forces commander for the