Conflict between the Siamese and Cambodians led to the conquest of the Cambodian capital at the end of the sixteenth century, leading to Siam’s political domination of Cambodia.

Before the rise of major Thai (Siamese) Siam kingdoms in mainland Southeast Asia, the Cambodians (also known as the Khmer) were culturally and politically dominant in modern Cambodia Cambodia , in much of modern Thailand, and in parts of southern Vietnam. During the 1200’, powerful Thai principalities (kingdoms) began to challenge the Cambodians, and the kings of the rising power of the Thai kingdoms, Ayutthaya Ayutthaya , continued to struggle against powerful neighbors throughout the kingdom’s history. In 1431, the Siamese of Ayutthaya attacked and sacked the Cambodian capital at Angkor. Rival forces of the kingdom of Burma Burma;and Thai peoples[Thai] (now called Myanmar) exerted continual pressure on Ayutthaya too. In 1569, the Burmese king Bayinnaung conquered Ayutthaya and its surrounding territory. Siamese-Cambodian Wars (c. 1580-c. 1600)[Siamese Cambodian Wars (c. 1580-c. 1600)]
Naresuan
Chetta I
Barom Reachea IV
Bayinnaung
Naresuan
Chetta I
Barom Reachea IV
Maha Thammaracha

The weakness of the Siamese enabled the Cambodians once again to stage several invasions of central Thailand. In 1570, 1575, and 1578, Cambodia invaded Ayutthaya, expecting that the kingdom that had been subjected to Burmese rule would be an easy source of loot. The Siamese, however, succeeded in repelling the Cambodian forces, but the invasions inflicted great hardship on the local population.

Naresuan was the most active Siamese defender. The Burmese had appointed Naresuan as governor of the Siamese province of Phitsanulok Phitsanulok in 1571. However, Naresuan declared himself independent of Burma in 1584 and, through continual fighting, managed to reestablish the independence of Ayutthaya.

About 1580, the Cambodians reopened the war against the Siamese from the east. In that year, the Cambodian king Chetta I raised an army and captured the Siamese city of Phet Buri. The following year, Chetta’s forces again pushed into the eastern part of Siam and took large numbers of captives.

Chetta had helped to encourage European involvement in Southeast Asian affairs. He surrounded himself with Spanish and Portuguese bodyguards, who were soldiers of fortune. He also maintained contact with the Spanish authorities who had recently established themselves in Manila, the Philippines.

For a time, Naresuan was too preoccupied with his struggles against the Burmese to give much attention to the Cambodians. The Siamese and Cambodians even paused in their rivalry for a brief alliance. In 1586, during yet another invasion of Siamese territory, Chetta sent forces under the command of his brother Barom Reachea IV to help Naresuan defeat Burmese troops who had invaded the northern Thai kingdom of Chiang Mai. The alliance was short-lived. The Cambodian king’s brother apparently treated Naresuan in a manner that the Siamese prince considered disrespectful. Naresuan expressed his anger by cutting off the heads of some prisoners and then putting the heads on stakes close to Barom Reachea’s boat. The mutual insults propelled Siam and Cambodia into war. When Burma invaded Siam again the next year, Chetta took advantage of the occasion to stage an invasion from the other side. After defeating the Burmese, Naresuan returned his attention to the Cambodian enemy. The Siamese prince recaptured his lands from Chetta’s forces and then drove into Cambodia. Naresuan captured Battambang and Pursat in Cambodia and then advanced to Lavek, the Cambodian capital at that time. Lack of supplies, however, forced the Siamese to return home.

Burma’s puppet king of Siam, Maha Thammaracha (r. 1569-1590), died in 1590, and Naresuan became the new king of the Siamese kingdom of Ayutthaya. Naresuan had been planning to attack Cambodia in 1592, when the Burmese made another effort to retake Siam. After defeating Burma, Naresuan focused again to the east. In 1593, he raised an army said to consist of between fifty thousand and one hundred thousand troops. This time, the march into Cambodia was a series of victories for the Siamese. Naresuan’s forces faced almost no resistance when they took the Cambodian strongholds of Battambang and Pursat. Barom Reachea, with whom Naresuan had quarreled during the brief alliance, brought a force of thirty thousand soldiers to Boribun but fled before putting up a fight, and Boribun too fell. As Naresuan advanced on the Cambodian capital at Lavek, he met Siamese troops moving in from the north.

The fight for the Cambodian capital was much more difficult than were earlier battles, and both sides suffered heavy casualties. Chetta appealed for help from the Spanish at Manila, but the Europeans did not arrive in time to help him. Finally, in July of 1594, the Siamese managed to take the city. According to Thai legend but disputed by modern historians, Naresuan ordered Chetta executed so that he could bathe his feet in the blood of the Cambodian king. Historians, instead, argue that Chetta had escaped and made his way to Luang Prabang in Laos, where he died two years later.

The Siamese took Barom Reachea prisoner and held him for several years. The Kingdom of Cambodia fell into civil war in the last few years of the sixteenth century, with several changes of rulers. In 1597, the Spanish, who had arrived too late to help Chetta, nevertheless placed one of Chetta’s sons on the throne. The Cambodian royal family asked Naresuan to return Barom Reachea as the new Cambodian ruler and, in return, promised allegiance to Siam. In 1603, Siamese soldiers enabled Barom Reachea to seize the throne and rule for the next decade and a half as the vassal of Siam.

The Siamese-Cambodian Wars of the sixteenth century changed the balance of power in mainland Southeast Asia decisively. Cambodia, which had dominated the region when the Siamese kingdoms began to appear in the thirteenth century, had been in decline for centuries, but Cambodia was still a state to be reckoned with when Chetta I came to the throne.

From Naresuan’s conquest of Lavek until the French claimed Cambodia in the nineteenth century, Cambodia was a vassal state of Siam, which was later renamed Thailand. Although the Siamese continued to fight against the Burmese, Cambodia never again represented a serious threat either to the kingdom centered in Ayutthaya or to the succeeding Siamese state ruled from Bangkok. Naresuan became a Thai national hero and a symbol of Thai independence because of his victories against both the Burmese and the Cambodians.

• Chandler, David. A History of Cambodia. 3d ed. Boulder, Colo.: Westview Press, 2000. One of the best general histories of Cambodia, this edition updates earlier editions and traces events in Cambodia from the first century through the late twentieth century.
• 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.
• Hall. D. G. E. A History of South-East Asia. 4th ed. New York: St. Martin’s Press, 1981. A standard, comprehensive history of the region.
• Wood, W. A. R. A History of Siam. 1924. Reprint. Bangkok, Thailand: Wachrin, 1994. Often based as much on legend as on fact, this often-cited work is one of the first English language works to attempt a scholarly understanding of Siamese history.
• Wyatt, David K. Thailand: A Short History. New Haven, Conn.: Yale University Press, 1986. Provides an introduction to Thai history, including coverage of the Ayutthaya period.

1450’s-1529: Thai Wars

1454: China Subdues Burma

1469-1481: Reign of the Ava King Thihathura

c. 1488-1594: Khmer-Thai Wars

1527-1599: Burmese Civil Wars

1548-1600: Siamese-Burmese Wars

1558-1593: Burmese-Laotian Wars

1565: Spain Seizes the Philippines