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
Western Union (alliance) DC. The need to back up the commitments of the North Atlantic Treaty with appropriate political and military structures led to the creation of the North Atlantic Treaty Organisation (NATO). In December 1950, with the appointment of General Eisenhower as the first Supreme Allied Commander Europe (SACEUR), the members of the Treaty of Brussels decided to transfer the headquarters, personnel, and plans of the Western Union Military Organisation (WUDO) to NATO. NATO's Supreme Headquarters Allied Powers Europe (SHAPE) took over responsibility for the defence of Western Europe, while the physical headquarters in Fontainebleau were transformed into NATO's Headquarters, Allied Forces