First Indochina War: The Geneva Conference partitions Vietnam into North Vietnam and South Vietnam.

Dwight D. Eisenhower pledges United States support to South Vietnam

Operation Passage to Freedom, the evacuation of 310,000 Vietnamese civilians, soldiers and non-Vietnamese members of the French Army from communist North Vietnam to South Vietnam following the end of the First Indochina War, ends.

Ngô Đình Diệm declares himself Premier of South Vietnam.

Ngo Dinh Diem of South Vietnam survived a communist shooting assassination attempt in Ban Me Thuot.

President Ngo Dinh Diem of South Vietnam becomes the first foreign head of state to make a state visit to Australia.

A parcel bomb sent by Ngo Dinh Nhu, younger brother and chief adviser of South Vietnamese President Ngo Dinh Diem, fails to kill King Norodom Sihanouk of Cambodia.

A military coup against President Ngo Dinh Diem of South Vietnam is crushed.

United States President John F. Kennedy sends 18,000 military advisors to South Vietnam.

A protest against pro-Catholic discrimination during the Buddhist crisis is held outside South Vietnam's National Assembly, the first open demonstration during the eight-year rule of Ngo Dinh Diem.

The Buddhist crisis: Soldiers of the Army of the Republic of Vietnam attack protesting Buddhists in Huế, South Vietnam, with liquid chemicals from tear gas grenades, causing 67 people to be hospitalised for blistering of the skin and respiratory ailments.

Buddhist monk Thich Quang Duc burns himself with gasoline in a busy Saigon intersection to protest the lack of religious freedom in South Vietnam.

South Vietnamese President Ngô Ðình Diệm is assassinated following a military coup.

Vietnam War: Following the November 1 coup and execution of President Ngo Dinh Diem, coup leader General Duong Van Minh takes over leadership of South Vietnam.

Vietnam War: Newly sworn-in US President Lyndon B. Johnson confirms that the United States intends to continue supporting South Vietnam both militarily and economically.

Vietnam War: at a rally in Saigon, South Vietnamese Prime Minister Nguyen Khanh calls for expanding the war into North Vietnam.

Vietnam War: Viet Cong forces attack the capital of Dinh Tuong Province, Cai Be, killing 11 South Vietnamese military personnel and 40 civilians (30 of which are children).

Vietnam War: 5,000 more American military advisers are sent to South Vietnam bringing the total number of United States forces in Vietnam to 21,000.

Vietnam War: A ''coup d'état'' replaces Duong Van Minh with General Nguyen Khanh as President of South Vietnam. A new constitution is established with aid from the U.S. Embassy.

North Vietnamese Army begins infiltration of South Vietnam.

Vietnam War: The first United States combat troops are sent to South Vietnam.

Vietnam War: American warships begin the first bombardment of National Liberation Front targets within South Vietnam.

Civilian Prime Minister of South Vietnam Phan Huy Quat resigned after being unable to work with a junta led by Nguyen Cao Ky.

Nguyen Cao Ky became Prime Minister of South Vietnam at the head of a military junta; General Nguyen Van Thieu became the figurehead chief of state.

Vietnam War: The United States uses B-52 bombers to attack National Liberation Front guerrilla fighters in South Vietnam.

Vietnam War: U.S. President Lyndon B. Johnson announces his order to increase the number of United States troops in South Vietnam from 75,000 to 125,000.

Vietnam War: In a follow-up to August's Operation Starlight, United States Marines and South Vietnamese forces initiate Operation Piranha on the Batangan Peninsula.

Vietnam War: The 1st Cavalry Division (United States) (Airmobile), in conjunction with South Vietnamese forces, launches a new operation seeking to destroy North Vietnamese forces in Pleiku in the II Corps Tactical Zone (the Central Highlands).

Vietnam War: In response to U.S. President Lyndon B. Johnson's call for "more flags" in Vietnam, Philippines President Elect Ferdinand Marcos announces he will send troops to help fight in South Vietnam.

Lyndon B. Johnson states that the United States should stay in South Vietnam until Communist aggression there is ended.

Military Prime Minister of South Vietnam Nguyen Cao Ky sacked rival General Nguyen Chanh Thi, precipitating large-scale civil and military dissension in parts of the nation.

After a policy dispute, Prime Minister Nguyen Cao Ky of South Vietnam's ruling junta launches a military attack on the forces of General Ton That Dinh, forcing him to abandon his command.

A Canadair CL-44 chartered by the United States military crashes into a small village in South Vietnam, killing 129.

Vietnam War: US and South Vietnamese forces engage Viet Cong troops in the Mekong Delta.

Operation Igloo White, a US electronic surveillance system to stop communist infiltration into South Vietnam begins installation.

Vietnam War: The Tet Offensive begins when Viet Cong forces launch a series of surprise attacks in South Vietnam.

Vietnam War: The execution of Viet Cong officer Nguyen Van Lem by South Vietnamese National Police Chief Nguyen Ngoc Loan is videotaped and photographed by Eddie Adams. This image helped build opposition to the Vietnam War.

Vietnam War: The Tet Offensive is halted; South Vietnam recaptures Hué.

Vietnam War: South Vietnamese opposition leader Trương Đình Dzũ is sentenced to five years hard labor for advocating the formation of a coalition government as a way to move toward an end to the war.

Vietnam War: Operation Commando Hunt initiated. The goal is to interdict men and supplies on the Ho Chi Minh Trail, through Laos into South Vietnam.