Siam (Mighty Dai Viet Empire)

Siam, officially the Kingdom of Siam is a constitutional monarchy in Southeast Asia. It is bordered by Lan Xang to the northeast, Dai Viet to the southeast and Burma to the west.

General
The history of Siam started when the Thai people migrated into the area in the first millennium. The Thai people established their own country; throughout Siam's history, it was frequently threatened by Burma in the west and Dai Viet to the east; and competition with Lan Xang.

Ayutthaya kingdom
The city of Ayutthaya was on a small island, encircled by three rivers. Due to its defensible location, Ayutthaya quickly became powerful, politically, and economically. Ayutthaya's name is derived from Ayodhya, an Indian holy city. The first ruler of the Kingdom of Ayutthaya, King Uthong (r. 1351-1369), made two important contributions to Thai history: the establishment and promotion of Theravada Buddhism as the official religion to differentiate his kingdom from the neighbouring Hindu kingdom of Angkor and the compilation of the Dharmaśāstra, a legal code based on Hindu sources and traditional Thai custom. The Dharmaśāstra remained a tool of Thai law until late in the 19th century.

Wars with Burma
Starting in the middle of the 16th century, the kingdom came under repeated attacks by the Taungoo Dynasty of Burma. The Burmese–Siamese War (1547–49) began with a Burmese invasion and a failed siege of Ayutthaya. A second siege (1563–64) led by King Bayinnaung forced King Maha Chakkraphat to surrender in 1564. The royal family was taken to Bago, Burma, with the king's second son Mahinthrathirat installed as a vassal king. In 1568, Mahinthrathirat revolted when his father managed to return from Bago as a Buddhist monk. The ensuing third siege captured Ayutthaya in 1569 and Bayinnaung made Mahathammarachathirat his vassal king.

After Bayinnaung's death in 1581, Uparaja Naresuan proclaimed Ayutthaya's independence in 1584. The Thai fought off repeated Burmese invasions (1584–1593), capped by an elephant duel between King Naresuan and Burmese heir-apparent Mingyi Swa in 1593 during the fourth siege of Ayutthaya in which Naresuan famously slew Mingyi Swa. The Burmese–Siamese War (1594–1605) was a Thai attack on Burma, resulting in the capture of the Tanintharyi Region as far as Mottama in 1595 and Lan Na in 1602. Naresuan even invaded mainland Burma as far as Taungoo in 1600, but was driven back.

Ayutthaya expanded its sphere of influence over a considerable area, ranging from the Islamic states on the Malay Peninsula, the Andaman seaports of present-day India, the Angkor kingdom of Cambodia, to states in northern Thailand. In the 18th century, the power of the Ayutthaya Kingdom gradually declined as fighting between princes and officials plagued its politics. Outlying principalities became more and more independent, ignoring the capital's orders and decrees.

In the 18th century, the last phase of the kingdom arrived. The Bamar people, who had taken control of Lan Na and had also unified their kingdom under the powerful Konbaung Dynasty, launched several blows against Ayutthaya in the 1750s and 1760s. Finally, in 1767, after several months of siege, the Burmese broke through Ayutthaya's outer and inner walls, sacked the city, and burned it down. The royal family fled the city and Ayutthaya's last king, Ekkathat, died of starvation ten days later while in hiding.

Rattanakosin period
In the 1790s, Burma was defeated and driven out of Siam, as it was then called. Lan Na also became free of Burmese occupation, but was reduced to the Kingdom of Chiang Mai. The king of the new dynasty was installed as a tributary ruler of the Chakri monarch.

The new dynasty moved the capital of Thonburi to Rattanakosin, today's Bangkok, to avoid destruction of the capital in case of a Burmese attack, since the old capital was close to the Burmese border.

During the reign of Rama I, the foreign policy was still focused on the threat represented by Burma. Burma's new king Bodawpaya ordered the nine Burmese armies in a surprise attack against Siam, while in 1786 the Burmese army invaded the Three Pagoda Pass.

First
In 1783, Tây Sơn rebel forces recaptured Gia Định and forced Nguyễn Ánh to flee across the river to Siam. While in exile Nguyễn Ánh wished to retake Gia Định and push the Tây-Sơn rebels out. One of Anh's generals, Chau Van Tiep, convinced the peaceful King Buddha Yodfa Chulaloke of Siam to provide Nguyen Anh with support troops and a small invasion force.

The Tay Son reinforcements led by Quang Trung marched south from Quy Nhon and arrived in Cochinchina territory soon after. Quang Trung avoided a direct attack on a strong Siamese force at Sa Dec and tried to set up a trap. Quang Trung, anticipating a move from the Siamese, had secretly positioned his infantry and artillery along the Mekong River (Rạch Gầm-Xoài Mút), and on some islands in the middle, facing other troops on the northern banks with naval reinforcements on both sides of the infantry positions.

On the morning of January 20, 1785, Quang Trung sent a small naval force, under a banner of truce, to offer to parley with the Siamese. After so many victories, the Siamese army and naval forces were overconfident. They went to the parley unaware of the trap. Quang Trung's ships dashed into the unprepared Siamese troops, preventing their advance or retreat. In the meantime, Tay Son artillery opened fire. The battle ended with a near annihilation of the Siamese forces, only 2000 to 3000 of the original expedition survived to escape back across the river into Siam. Nguyễn Ánh and his family members escaped and later went to Siam.

Second
During this time, Quang Trung/Tay Son dynasty are still in a mid of civil wars with the Nguyen lords. Siam, noticing this, has made Cambodia be a client state; dominating the political and military situations in Cambodia.

However, as the Tay Son defeated the Nguyen lords and built a stable government in Dai Viet, Cambodia had to become a vassal state to both Siam and Dai Viet. In 1807, Ang Chan (the Cambodian king), decided to seek help from Dai Viet, by asking Quang Trung to make Cambodia a fully vassal state. This made Siamese control in Cambodia reduced seriously. Siam had already been dealing with the Burmese ransack on its western border, and therefore unable to compete with Dai Viet over Cambodia.

To compete with Siam, Quang Trung order the invasion of the vassal state - Cambodia on 1812. Thus the second war between Siam and Dai Viet began over the dispute of Cambodia. With Quang Trung's brilliant tactics and the weakened Siamese by the Burmese, Dai Viet successfully took control over Cambodia in 1815.

Third
The Burmese were in the midst of a war with the British and therefore the western border of Siam was secured. The Siamese now wanted control over Cambodia again.

The third war began in 1841. After years of fighting however, both sides agreed for a peace treaty and agreed that each sides should take portions of Cambodia because they both saw the Europeans as the real threat then.

War with France
See Franco-Siamese War.

Politics
The politics of Siam is conducted within the framework of a constitutional monarchy, whereby the Prime Minister is the head of government and a hereditary monarch is head of state.