In 1954, as the defeated French forces left the State of Vietnam, Ngô Đình Diệm, a devout Roman Catholic, became the first prime minister. In 1956, a government-controlled referendum determined that South Vietnam should become a republic rather than stay under the control of Emperor Bảo Đại (who was living in Cannes, on the French Riviera). Ngô Đình Diệm appointed himself the first President of the Republic of Vietnam (South Vietnam). He then appointed his younger brother, Ngô Đình Nhu, to be his chief advisor and head of both South Vietnam’s secret police and its largest intelligence agency. During 1963, a campaign of civil resistance led by Buddhist monks protested religious discrimination. The government’s brutal treatment of Buddhists convinced many that Ngô Đình Diệm should go. While the United States publicly denied playing any part in the 1963 coup that overthrew Diệm, it was revealed that American officials had met with and encouraged the generals who planned the coup. Both Ngô Đình Diệm and his brother, Ngô Đình Nhu, were executed on 2 November 1963. 1st elected president of South Vietnam, Ngo Dinh Diem. 1st president vietnam, ngo dinh diem, republic of vietnam, south vietnam, assassination, execution