The most prevalent religion in Vietnam is Buddhism. Chinese conquerors and Indian traders introduced the faith around the second century B.C. It became the state religion sometime during the Ly dynasty of the 10th to 12th centuries A.D.
Buddhism is an integral part of Vietnamese culture. Nearly 50 million Vietnamese, about 55 percent of the population, are practicing Buddhists.
In May 1963, the South Vietnamese President Diem would not allow Buddhists to fly flags at a religious celebration. The Vietnamese protested, and government troops killed nine demonstrators. A Buddhist monk named Thich Quang Duc immolated himself to protest the persecution, embarrassing the Vietnamese government. However, instead of working with the Buddhists, the Vietnamese government sent troops into temples and killed hundreds.