The end of the Second World War saw anti-Japanese Việt Minh guerrilla forces, led by communist fighter Ho Chi Minh, proclaiming the establishment of the Democratic Republic of Vietnam in Hanoi in September 1945. In 1949, anti-communist politicians formed a rival government in Saigon led by former emperor Bảo Đại. A 1955 referendum on the state's future form of government was highly contested and resulted in the deposal of Bảo Đại by Prime Minister Ngô Đình Diệm, who proclaimed himself president of the new republic on 26 October 1955. After the 1954 Geneva Conference, it abandoned its claims to the northern part of the country and established its sovereignty over the southern half of Vietnam consisting of Cochinchina ("Nam Kỳ") – a former French colony and parts of Annam ("Trung Kỳ") – a former French protectorate. Diệm was killed in a military coup led by general Dương Văn Minh with help from the CIA in 1963, and a series of short-lived military governments followed. General Nguyễn Văn Thiệu then led the country after a US-encouraged civilian presidential election from 1967 until 1975.