The early history of the Bru remains somewhat obscure. Researchers believe that the ancestors of the Bru were members of the kingdom of the
Khmers of
Angkor which dominated large parts of
Cambodia,
Laos and
Thailand, circa the 9th century and 13th century. This is also based upon the relationship between the Mon-Khmer languages and the Bru. There is common speculation that the Bru and other Mon-Khmer groups were pushed out of valley lands by Thai-speaking peoples migrating from China, but there is no evidence to this effect, as those lands were occupied by Mon and Khmer populations who were distinct linguistically and culturally from the Bru or other Mon-Khmer groups of Laos, who as indigenous people, may have always lived in remote, isolated areas. A small part of the Bru migrated from
Annamite Range (Vietnamese: dãy Trường Sơn) to
Đắk Lắk since late April 1972. In 2019, the Bru population in Đắk Lắk is 2,659 people, more crowded than their population in Thừa Thiên–Huế (1,389 people). During the
Vietnam War, the Bru suffered greatly as a result of the conflict that surrounded them. During and following the
Vietnam War the Bru people in Thailand were heavily involved in revolutionary activities against the local Thai governments. The Thai central government combated these activities by increasing Thai military presence as well as increasing spending for economic development. In Vietnam, during the war, the Bru people (called Vân Kiều in Vietnamese language) provided significant support for the movement of
Viet Minh and later the People's Republic of Vietnam. They later adopted the surname "Ho" to express their gratitude to President
Ho Chi Minh. ==Religion==