In spring 1955 anti-French sentiment led Vietnamese nationalists to call for removal of Bảo Đại, who was head of Vietnam’s provisional government.
Ngo Dinh Diem then set up a referendum between himself and Bảo Đại for October 1955.
In October 1955, Diem proclaimed South Vietnam the Republic of Vietnam and himself as its first president.
Condemning the northern government as authoritarian, Diem blocked the national elections that the 1954 Geneva Accords mandated, making certain that Vietnam was not united under Communist rule.