Supreme Headquarters Allied Powers Europe government offered Camp Casteau, a 2 km² Belgian Army summer training camp near Mons, which was an area in serious need of additional economic investment. In September 1966, NATO agreed that Belgium should host SHAPE at Casteau. SHAPE closed its facility at Rocquencourt near Paris on 30 March 1967, and the next day held a ceremony to mark the opening of the new headquarters at Casteau. The drawdown of the British Mediterranean Fleet, the military difficulties of the politically decided command structure, and the withdrawal of the French from the military command structure forced a rearrangement of the command arrangements
Supreme Headquarters Allied Powers Europe was shunted aside in favor of Air Force general Joseph Ralston. Although the move was publicly characterized as a purely administrative move necessitated by Clark's approaching retirement and the lack of an open four-star slot for the highly respected Ralston [a reality which would have compelled him to either accept a temporary demotion to two-star rank or retire from the service], Clark's relief has been often seen as a slap at the general on the part of a Pentagon leadership that had been very much at odds with him during the Kosovo war the previous spring. From the early 2000s