Burmese–Siamese War (1547–1549)

The Burmese–Siamese War (1547–1549) (; ), also known as the Tabinshwehti war () was the first war fought between the Toungoo dynasty of Burma and the Ayutthaya Kingdom of Siam, and the first of the Burmese–Siamese wars that would continue until the middle of the 19th century. The war is notable for the introduction of early modern warfare to the region. It is also notable in Thai history for the death in battle of Siamese Queen Suriyothai on her war elephant; the conflict is often referred to in Thailand as the War that Led to the Loss of Queen Suriyothai ().

The casus belli have been stated as a Burmese attempt to expand their territory eastwards after a political crisis in Ayutthaya as well as an attempt to stop Siamese incursions into the upper Tenasserim coast. The war, according to the Burmese, began in January 1547 when Siamese forces conquered the frontier town of Tavoy (Dawei). Later in the year, the Burmese forces led by Gen. Saw Lagun Ein retook the Upper Tenasserim coast down to Tavoy. Next year, in October 1548, three Burmese armies led by King Tabinshwehti and his deputy Bayinnaung invaded Siam through the Three Pagodas Pass. The Burmese forces penetrated up to the capital city of Ayutthaya but could not take the heavily fortified city. One month into the siege, Siamese counterattacks broke the siege, and drove back the invasion force. A truce was agreed in February 1549. The Burmese negotiated a safe retreat in exchange for the return of two important Siamese nobles (the heir apparent Prince Ramesuan, and Thammaracha of Phitsanulok) whom they had captured.

The successful defense preserved Siamese independence for 15 years. However, this war was not decisive. The next Burmese invasion in 1563 would force a Siamese surrender in February 1564, and make Ayutthaya a vassal state of Burma for the first time.

Background

Rise of Toungoo Dynasty

Burma in the 15th century was divided into four principal power centers: the Ava Kingdom in present-day central Burma, the Mon-speaking Hanthawaddy kingdom on the southern coast, the Mrauk-U Kingdom (Arakan) in the west, and various Shan States in the east and the north. Beginning in the 1480s, Ava began to disintegrate into even smaller kingdoms. By the early 15th century, Ava's former vassals—Mohnyin (and its allies Confederation of Shan States) in the north and the Prome Kingdom (Pyay) in the south—were regularly raiding their former overlord's territory with increasing frequency and intensity.Harvey 1925: 100–109

During this period of tumult, Mingyi Nyo, then governor of Toungoo (Taungoo), a small region located at the southeastern corner of Ava Kingdom also declared independence in 1510, and largely stayed out of the internecine fighting in the following years. When Ava fell to the combined forces of the Confederation and Prome in 1527, many people fled to Toungoo, the only region in Upper Burma at peace.Fernquest 2005: 20–50Harvey 1925: 124–125

In 1530, Mingyi Nyo's son 14-year-old Tabinshwehti succeeded him as king. Toungoo's stability continued to attract manpower from the surrounding regions, especially after 1533 when the Confederation sacked its erstwhile ally Prome. The tiny Toungoo was now the only ethnic Burman-led kingdom, and one surrounded by much larger kingdoms. Fortunately for Toungoo, the Confederation was distracted by internal leadership disputes, and Hanthawaddy, then the most powerful kingdom of all post-Pagan kingdoms, was weakly led. Tabinshwehti decided not to wait until the larger kingdoms' attention turned to him.

In 1534, Tabinshwehti and his deputy Bayinnaung, then a couple of 18-year-olds, launched their first military campaign against Hanthawaddy. It was the first of a series of wars by Toungoo that would engulf western and central mainland Southeast Asia for the next 80 years. In 1538–1539, the upstart kingdom captured Hanthawaddy's capital Pegu (Bago), and in May 1541, Martaban (Mottama) and Moulmein (Mawlamyaing).Harvey 1925: 153–158Htin Aung 1967: 106–112 Significantly, for the first time, the Burmese and the Siamese shared a common border in the upper-Tenasserim coast.

For the next six years, Toungoo was busy fighting against Hanthawaddy's allies: Prome (1542), the Confederation (1542–1544), and Prome's ally Mrauk-U (1546–1547). On the eve of the Siamese war, in 1547, Toungoo controlled a Lower Burma region from Pagan (Bagan) in the north to Moulmein in the south.

Crisis in Ayutthaya

King Chairacha of Ayutthaya was a scion of the Suphannaphum Dynasty, which took control of Siam from the Uthong Dynasty in 1409. He came to the throne in 1533 after usurping the crown of his five-year-old nephew, Phra Ratsadathirat, who had reigned for only four months.Wood 1924: 100 The boy's father was King Borommarachathirat IV, Chairacha's half-brother. The child-king was subsequently executed by his uncle.Wood 1924: 101 King Chairacha died in 1546 after reigning for thirteen years, leaving the throne to his eleven-year-old son, Prince Kaeofa, who was crowned King Yot Fa.Wood 1924: 108

As the new king had not come of age, the role of regent was assumed by his mother, Chairacha's chief consort Si Sudachan (, also spelled Sri Sudachan), who was a descendant of the Uthong royal house. Chairacha's half-brother and Uparaja, Prince Thianracha, was another contender for the regency. To avoid court intrigues and conflict with Si Sudachan, Prince Thianracha retreated to a monastery as a monk. It is said that even before the previous King's death, Si Sudachan was having an adulterous relationship with a paramour styled Khun Chinnarat, who was keeper of the Royal chapel or cloister (, Ho Phra Thep Bidon) within the Royal Palace of Ayutthaya. Fernão Mendes Pinto, a contemporary Portuguese explorer, recorded a rumour alleging that Si Sudachan had poisoned her husband in order to take control of the throne, and perhaps to restore the fallen House of Uthong to power. In support of these allegations, she had many prominent officials executed, including the aged and high-ranking Phraya Mahasena (Minister of Defence), and replaced them with her favourites.Wood 1924: 109 It was also recorded that she was heavily pregnant and soon gave birth to a daughter; unable to conceal this secret, she mounted a coup, removed her son and put her paramour on the throne. He was crowned as King (or Khun) Worawongsathirat. It was said that the young King Yot Fa was either executed or poisoned by his mother.Wood 1924: 110

Worawongsathirat's reign was short. Within 42 days several nobles and government officials of Ayutthaya plotted to remove him from the throne. The conspirators were led by Khun Phiren Thorathep, a descendant on his father's side to the kings of Sukhothai and a relation on his mother's side to King Chairacha. The usurper was lured from the safety of the palace into the jungle with a promise of capturing a large elephant. As the usurper king, Si Sudachan and their infant daughter proceeded by royal barge, Khun Phiren Thorathep and his conspirators sprang an ambush, killing all three.Wood 1924: 111Damrong Rajanubhab 2001: 14 Thianracha was immediately invited to leave the Sangha and assume the throne as King Maha Chakkraphat.Damrong Rajanubhab 2001: 15 One of his first acts was to appoint Khun Phiren Thorathep as King of Sukhothai (but as a vassal to himself) with a capital at the great fortified town of Phitsanulok. The king then bestowed upon him the title Maha Thammaracha (a title used by the last four kings of Sukhothai), along with the hand of his daughter Princess Sawatdirat in marriage.Wood 1924: 112Damrong Rajanubhab 2001: 13

Tenasserim (1547–1548) The war began in 1547.Harvey 1925: 158 The casus belli has been stated as an attempt by the Toungoo Dynasty of Burma to expand its territory eastwards after a political crisis in Ayutthaya as well as an attempt to stop Ayutthaya's incursions into the upper Tenasserim coast. According to the Burmese chronicles, a Siamese force of 6,000 had occupied Tavoy (Dawei) in the Upper Tenasserim coast, which he considered his territory, by January 1547.Burmese chronicles (Hmannan Vol. 2 2003: 238) say Tabinshwehti learned of the Siamese occupation of Tavoy before he agreed to a truce with King Min Bin of Mrauk-U on 31 January 1547 (9th waxing of Tabodwe 908 ME). As frontiers in the pre-modern period were less defined and often overlapped,Fernquest 2005: 286 the "occupation" may have been an attempt by Ayutthaya to reinforce the frontier town, which was claimed by Toungoo. At any rate, Tabinshwehti sent a sizable force of 12,000 (8,000 army, 4,000 navy) led by Saw Lagun Ein, viceroy of Martaban, to take over Tavoy c. October/November 1547.The invasion likely began in late October/early November 1547 although Burmese chronicles (Hmannan Vol. 2 2003: 238–239) simply say the attack on Tavoy began in 909 ME (30 March 1547 to 28 March 1548). The attack probably did not take place in early 1547 since Tabinshwehti's troops evacuated southern Arakan only on 26 March 1547 (5th waxing of Late Tagu 908 ME). The troops would have arrived back only in mid-to-late April, leaving just about a month for a military campaign before the rainy season began in June. The invasion, like most wars by the Burmese kings, probably began toward the end of rainy season and after the end of Buddhist Lent, which ended on 13 October 1547 (New moon of Thadingyut 909 ME) that year. A joint land-naval attack on Tavoy drove out the Siamese forces led by the Lord of Kanchanaburi to lower Tenasserim.Hmannan Vol. 2 2003: 238–239

Invasion of mainland Siam (1548–1549)

Burmese battle plan Tabinshwehti was not satisfied, and planned an invasion of Siam itself. By October 1548, he had assembled another 12,000-strong force that also included about 400 Portuguese mercenaries led by Diogo Soares.Harvey 1925: 158–159 The invasion force would have been equipped with the conventional weapons of the day: swords, bow and arrows, and spears.Quaritch Wales 1952: 145 The more elite members would also carry matchlocks or muskets.Quaritch Wales 1952: 189 These early modern weapons having been introduced to the two kingdoms by the Portuguese a few decades earlier.

Tabinshwehti took personal command and gathered his forces at Martaban (Mottama).Phayre 1967: 100 The invasion forces were organized into three main armies: the vanguard army led by Bayinnaung, the main army led by Tabinshwehti, and the rearguard army led by Thado Dhamma Yaza and Mingyi Swe, each with a strength of 4,000 troops. Their route of invasion was via the Three Pagodas Pass towards Kanchanaburi, and then to the capital Ayutthaya.

Start of invasion On 14 October 1548 (13th waxing of Tazaungmon 910 ME), the three Burmese armies left Martaban to start the invasion. The armies marched along the Ataran River toward the Three Pagodas Pass, entered Siam along the Khwae Noi River to the town of Sai Yok, then overland towards the Khwae Yai River. From there they travelled by boat toward the town of Kanchanaburi.Damrong Rajanubhab 2001: 16 Tabinshwehti travelled in great state with a massive retinue of elephants and servants. Many of these elephants carried muskets and bronze cannon; these were kept close to the king. Royal elephants were rafted across rivers, while the ordinary war elephants marched upstream to a ford. The Burmese king was accompanied by his crown prince Bayinnaung, Bayinnaung's thirteen-year-old son Nanda, and many richly attired lords. Hundreds of workmen marched ahead of the king's retinue, to pitch a richly decorated wooden camp, painted and gilded for the King's use, only to pack it up and pitch it at a new location every day.