Provisional Revolutionary Government of the Republic of South Vietnam

The Provisional Revolutionary Government of the Republic of South Vietnam (PRG, Chính phủ Cách mạng Lâm thời Cộng hòa miền Nam Việt Nam), was formed on June 8, 1969, by the Democratic Republic of Vietnam (North Vietnam) as an armed underground government opposing the government of South Vietnam (Republic of Vietnam) under President Nguyễn Văn Thiệu. Delegates of the National Liberation Front of South Vietnam (Viet Cong), as well as several smaller groups, participated in its creation.

The PRG was recognized as the government of South Vietnam by most socialist states and Malta. It signed the 1973 Paris Peace Treaty as an independent entity, separate from both South Vietnam and North Vietnam. After the Fall of Saigon on 30 April 1975, the PRG formally replaced the Republic of Vietnam to become the nominal and representative government of South Vietnam under the official name Republic of South Vietnam (Cộng hòa miền Nam Việt Nam), inheriting all properties, rights, obligations and sovereignty representation of the Republic of Vietnam. On 2 July 1976, the Republic of South Vietnam and the Democratic Republic of Vietnam constitutionally merged to form the current Socialist Republic of Vietnam.

History
The Provisional Revolutionary Government was preceded by the Vietnam Alliance of National, Democratic, and Peaceful Forces (VANDPF) made up of anti-government forces and headed by Trinh Dinh Thao. The Alliance was a collection of individuals who wanted a new South Vietnamese government but disagreed with the ever-present Northern Communist presence.

Discussions about forming an alliance had begun as early as 1966, but plans were disrupted when South Vietnamese intelligence agents apprehended a prominent anti-government figure, Ba Tra. Ba Tra gave the South Vietnamese government extensive information on anti-government forces working in the city. This setback was compounded by his identification of one of the key cadre in the financial division.

Under torture, Ba Tra identified more figures in the underground, who were then arrested. By 1967, the entire Saigon organization had been sent further underground.

In early 1969, the then-new American president, Richard Nixon, started a process of Vietnamization to allow the American Armed Forces to withdraw from South Vietnam.

1969–1975
On 8 June 1969 delegates from the Vietcong, the VANDPF, the People's Revolutionary Party (the South Vietnamese communist party) and "the usual assortment of mass organizations, ethnic groups, and geopolitical regions." met off Route 22 in Cambodia's Fishhook region and formed the Provisional Revolutionary Government (PRG). Banners displayed prominently at the convention proclaimed that "South Vietnam is independent, democratic, peaceful, and neutral".

Following the military and political results of the 1968 Tet Offensive and related military offensives in the South by Saigon and America, in which the Vietcong suffered serious military losses, the PRG was envisioned as a political counter-force that could influence international public opinion in support of reunification and in opposition to the United States and South Vietnam.

The declared purpose of the PRG was to provide a formal governmental structure to the Vietcong and enhance its claim of representing "the Southern people". Included in this strategy was the pursuit of a negotiated settlement to the war leading to reunification, organized during the initial phase of Vietnamization. According to Justice Minister Trương Như Tảng, the new group's main purpose was to help the Vietcong "acquire a new international stature."

During the period 1969–70, most of the PRG's cabinet ministries operated near the Cambodian border. Starting on 29 March to late April 1970, the US and South Vietnamese offensives forced the PRG to flee deeper into Cambodia. The stressful escape caused many of the PRG officials (such as Trương Như Tạng) to need extensive medical furloughs. After Trương Như Tạng returned, he noticed that new cadres from the north were causing problems for the non-communist members of the PRG. One member in particular, Ba Cap, harshly denounced most of the PRG as bourgeois. Tạng complained to the higher members of the North Vietnamese government, but was rebuffed. Tạng later saw this as the point when the PRG turned from being an independent South Vietnam-based alternative government to being a mouthpiece for North Vietnamese communists.

The central bodies of the PRG functioned as a provisional government. The PRG maintained diplomatic relations with many countries of the Non-Aligned Movement, such as Algeria and SFR Yugoslavia as well as with the Soviet Union and the People's Republic of China.

1975–1976
After the Fall of Saigon on 30 April 1975, the PRG assumed power in South Vietnam and subsequently participated in the reunification of Vietnam.

According to professor Long Vinh Ngo (University of Maine), mid-July 1975, the delegates of the Democratic Republic of Vietnam (Nguyễn Văn Lưu) and the Republic of South Vietnam (Đinh Bá Thi) applied to join the United Nations as two independent member states. On 11 August 1975, the United Nations Security Council introduced a referendum on reunification, which passed. North Vietnam and South Vietnam eventually reunited on 2 July 1976.

Music
The national anthem of the Government was Liberate the South (Vietnamese: Giải phóng miền Nam). The song was written in 1961 by Lưu Hữu Phước (1921–1989) and adopted at that time as the anthem of the National Liberation Front of South Vietnam (Viet Cong).

In 1966, Lưu Hữu Phước wrote a military song  (Tiến về Sài Gòn) as a propaganda to encourage the soldiers going to attack in Saigon in the Tet Offensive. The song was spread again during the fall of Saigon.