After the fall of Saigon on April 30, 1975, Vietnam became an unified country under control of North Vietnam’s communist government with Hanoi as its new capital. First of all, they decided to rename the country from Democratic Republic of Vietnam to Socialist Republic of Vietnam (SRV), explicitly indicating their desire to follow socialism and then communism. Besides, the People’s Revolutionary Party of South Vietnam was merged with Labour Party in North Vietnam and became Vietnamese Communist Party (VCP), the only one party in Vietnam. The VCP leader’s title was also changed from First Secretary, a term used by Chinese Communist, to Secretary General, used by Soviet Communist.
More @ The Vietnam War