Khmer-Thai Wars

By the end of the fifteenth century, the Thai people had completed their political integration and their kingdom, Siam, became a great regional power. The Khmer people, who had previously dominated the region, contributed significantly to Thai culture and sought to renew their former dominance. During the late fifteenth century and most of the sixteenth century, the two powers were in constant conflict.

Summary of Event

From the ninth to the eleventh century, the dominant power in Southeast Asia was the great Khmer Empire Khmer Empire , centered on Angkor, the magnificent capital and temple city on the Tonle Sap, a natural floodplain reservoir. The empire controlled much of what is now southern Vietnam, Laos, Thailand Thailand , and Cambodia Cambodia , which was its heartland. (The Khmer are also known as Cambodian.) The Thai chiefs were able to maintain some semblance of autonomy in the far uplands only. Thais were often taken into slavery, and in subsequent centuries, the struggle for Thai identity and independence produced a long-lasting enmity between the Thais and the Khmer. In the fifteenth and sixteenth centuries. this hostility broke out into a series of military conflicts. Khmer-Thai Wars (c. 1488-1594)[Khmer Thai Wars (c. 1488-1594)]
Borommaracha II
Borommaracha II
Ramathibodi II
Maha Thammaracha
Chetta I

The antagonism between the two peoples has colored the historical record, since much of the analysis of the period has been written by Thai scholars and has passed into Thai national consciousness through popular histories written for the schools. This can be attributed to the evolution of a Siamese (Thai) historiography made possible by Thai independence, while Cambodia came under colonial powers. Gradually, the Khmer came to accept the Thai interpretation of their cultural inferiority, even though Thai culture was influenced by Khmer ideas, customs, and art. An influential legend relates that the Siamese took two sacred statues containing scrolls of secret wisdom when they invaded Lovek in 1594, a battle that asserted Thai dominance over Cambodia for the next century. When the Thais smashed the statues, the occult knowledge was revealed and thus denied to the Khmer. The myth holds that the scrolls conferred superior knowledge on the Thais, thus justifying their overlordship. Thai ethnic and cultural prejudice against the Khmer persists into the twenty-first century.

By the fourteenth century, there were Thai kingdoms in the north (Lan Na, also known as Chiang Mai Chiang Mai ) and in the center at Sukhothai Sukhothai and Ayutthaya. In 1438, Ayutthaya Ayutthaya reduced Sukhothai to vassal status, which began a long series of Thai-against-Thai wars that would persist for seventy-five years. Ayutthaya was by this time both prosperous and powerful, its armies swelled with captives and its coffers enriched by trade. Conflict with Angkor had started earlier, with the greatest victory coming under Borommaracha, who seized and looted Angkor. The Khmer heir abandoned Angkor and fled to Phnom Penh. From this small base, later transferred to Lovet (Laweat), Khmer kings mounted a series of attacks and incursions into Ayutthayan territory to bolster their population and strengthen their fragile independence, which owed more to Ayutthaya’s concern with larger threats than to Khmer power.

In 1448, Borommaracha left a tightly managed kingdom, with mandatory military service and a levy of labor that required six months each year to be given to the king for public works. By tying the freedmen to the authority of local officials, the traditional patron system of personal allegiances was broken. This gave Ayutthaya both political control and flexibility, which was a large advantage over its rivals.

At the end of King Trailok’s long reign in 1488, Ayutthaya was enlarged through trade, and its expansion continued under his son. The coast of the Bay of Bengal and the Malay Peninsula came under Ayutthayan control, with rich mercantile trade in rice and cotton. When Ramathibodi II succeeded to the throne in 1491, he inherited a court that included many Khmer lawyers, scribes, and other professionals, who were recruited from the Angkorian elite of the conquered territories. Khmer royal traditions began to enter Ayutthayan court culture, elevating the king to a mystical, godlike personage, insulated from his subjects by layers of bureaucratic retainers. The Khmer became as the Greeks were to the Roman nobility—advisers, teachers of their sons, and culturally influential. Ramathibodi used his wealth to build major religious monuments and to expand and equip his army. Military power and awe-inspiring royal prestige combined to create a myth of imperial invincibility.

During the same period, the regions east of Ayutthaya coalesced into the kingdoms of Lan Sang, a Lao state centered on Vientiane, and Cambodia, known after its capital as the Kingdom of Lovek Lovek . The Khmer kings moved up the Mekong River from Phnom Penh and again occupied (but had not settled) Angkor. They guarded the Mekong Delta, which served as their economic base and transport waterway. While Ayutthaya was occupied with the Thai wars of the fifteenth to sixteenth centuries and harassed by constant threats from Burma, Lovek took advantage of Siamese instability to attack its old enemy and keep it off balance. Unable to conquer Siam, Lovek instead played Siam against other enemies of the Thais and kept them from aggressive action against the remnants of the Khmer kingdom.

One of the Khmer interventions was instigated by the Siamese crisis of 1547, when the death of King Chairacha resulted in a palace conspiracy in which the eleven-year-old successor was poisoned by the queen regent, who installed her lover as king. In reaction, the court nobility assassinated both and brought in a pious prince from his monastery as King Chakrapat (r. 1548-1569). His royal name, referring to the Buddhist wheel of righteousness, means “the wheel-turning king around whom the world revolves.” In the ensuing confusion, a major Burmese force attacked, sweeping through the north to the capital. The Khmer then took the opportunity to raid the easternmost province for loot and military conscripts. This incursion cost them dearly, as Chakrapat first negotiated a settlement with the Burmese and then turned on the hapless Khmer. In 1555-1556, Chakrapat struck Lovek with a large naval force and an army led by war elephants. The Khmer submitted, although they were permitted to keep their independence.

Soon, however, Ayutthaya faced a far more dangerous enemy as the Burmese Burma;and Thai peoples[Thai] returned to obliterate the landscape, drive out the population, and destroy the main Siamese cities. For twenty years, the Burmese ruled Siam through puppet king Maha Thammaracha (r. 1569-1590), Chakrapat’s son-in-law. The Burmese army garrisoned Ayutthaya and the now-vassal kingdom was left without defenses. The Burmese demolished most of the Thai fortifications, making the frontier districts difficult to defend. The Khmer again took advantage of the situation by striking Siam six times during this period—in 1570, 1575, 1578, twice in 1582, and in 1587. In each case, the Khmer sought to maintain Thai weakness and take captives to populate their own western provinces. Generally, they did not attempt to occupy the raided territories (although in 1582 they took Phetburi) because they did not want to raise the ire of the Burmese overlords. Finally, in 1580, the Thais persuaded the Burmese to allow some measure of self-protection, arguing that their weakened state left the eastern provinces open to pillage and depopulation and threatened rice production. The walls around Ayutthaya were replaced and strengthened.

Thai culture was shattered, but a new identity was forged in the next century, especially under the dynamic leadership of Naresuan. As the son of Maha Thammaracha and his chief queen (a daughter of Chakrapat), he was heir-presumptive to the Ayutthayan throne. He distinguished himself in battle against the Khmer, but as he built up Siamese forces in the 1580’, he came into repeated conflict with the Burmese. On three occasions between 1586 and 1587, he repulsed attempts to capture him and occupy the capital. During the last of these crises, in 1587, the Khmer took up their spoiler role and advanced into Thai territory, but Naresuan repelled them easily. When Burma mounted its last attack of this period in 1593, the Khmer made no attempt at a flanking sortie, and Naresuan defeated the Burmese at Nong Sarai, freeing Siam from serious threat for a century.

Able to turn his attention to other rivals, Naresuan struck Cambodia in several annual campaigns. Ayutsthaya had begun manufacturing arms and cannon, which it exported to China, Japan, and Melaka (Malacca). Now Naresuan turned the full force of an enlarged army on Cambodia. The desperate Khmer turned to the Portuguese for help, but they responded with only a handful of adventurers who were soon captured by Naresuan. With the fall of Lovek in 1594, Khmer king Chetta I (r. 1576-1594) fled to Laos and Cambodia was reduced to a tributary state after its many years of harassing attacks on Siam.


The Khmer-Thai Wars set the stage for the formation of modern Southeast Asia. As peace was established, war captives and refugees returned to Siam from Cambodia. Stability allowed for the establishment of new trade routes, and Siam became the dominant regional power. The first Western contacts had been made, but Siam was strong enough after this testing period to keep it from being colonized. Its neighbors, however, who were weakened by the conflicts, came under the influence and eventual control of European powers.

Further Reading

  • Chandler, David. A History of Cambodia. 3d ed. Boulder, Colo.: Westview Press, 2000. A standard history of Cambodia and the Khmer people from earliest times, written by a leading Western scholar.
  • Coedés, George. The Making of Southeast Asia. Translated by H. M. Wright. London: Routledge, Kegan & Paul, 1966. A classic introduction to early Southeast Asian history that examines the Siamese-Cambodian wars of the sixteenth century.
  • Mabbett, Ian, and David Chandler. The Khmers. Cambridge, Mass.: Basil Blackwell, 1995. A cultural history, with accounts of the kingdoms and their conflicts.
  • Wyatt, David. Thailand: A Short History. New Haven, Conn.: Yale University Press, 1984. One of the best accounts of the Thai peoples, covering all the kingdoms and their eventual grouping into Siam.

1450’s-1529: Thai Wars

1454: China Subdues Burma

1469-1481: Reign of the Ava King Thihathura

1505-1515: Portuguese Viceroys Establish Overseas Trade Empire

1511-c. 1515: Melaka Falls to the Portuguese

1527-1599: Burmese Civil Wars

1548-1600: Siamese-Burmese Wars

1558-1593: Burmese-Laotian Wars

c. 1580-c. 1600: Siamese-Cambodian Wars