not only military officers but government officials at every level. Soon both former Prime Ministers Aklilu Habte-Wold and Endelkachew Makonnen, along with most of their cabinets, most regional governors, many senior military officers and officials of the Imperial court were imprisoned. In August, after a proposed constitution creating a constitutional monarchy was presented to the emperor, the Derg began a program of dismantling the imperial government to forestall further developments in that direction. The Derg deposed and imprisoned the emperor on 12 September 1974. On 15 September, the committee renamed itself the Provisional Military Administrative Council (PMAC) and took full control of the government and all facilities within the government. The Derg chose Lieutenant General Aman Andom, a popular military leader and a Sandhurst graduate, to be its chairman and acting head-of-state. This was pending the return of Crown Prince Asfaw Wossen from medical treatment in Europe when he would assume the throne as a constitutional monarch. However, General Aman Andom quarreled with the radical elements in the Derg over the issue of a new military offensive in Eritrea and their proposal to execute the high officials of Selassie's former government. After eliminating units loyal to him—the Engineers, the Imperial Bodyguard and the Air Force—the Derg removed General Aman from power and executed him on 23 November 1974, along with some of his supporters and 60 officials of the previous Imperial government. Brigadier General Tafari Benti became the new Chairman of the Derg and the head of state, with Mengistu and Atnafu Abate as his two vice-chairmen, both with promotions to the rank of Lieutenant-Colonel. The monarchy was formally abolished in March 1975, and Marxism-Leninism was proclaimed the new ideology of the state. Emperor Haile Selassie died under mysterious circumstances on 27 August 1975 while his personal physician was absent. It is commonly believed that Mengistu killed him, either by ordering it done or by his own hand although the former is considered more likely. Both Derg and Haile Selassie government relocated numerous Amharas into southern Ethiopia, including present-day of the Oromia region, where they served in government administration, courts, church and school, where Oromo texts were eliminated and replaced by Amharic. The Abyssinian elites perceived the Oromo identity and languages as hindrances to Ethiopian national identity expansion. Under Mengistu's leadership After internal conflicts that resulted in the execution of General Tafari Benti and several of his supporters in February