Burmese – Siamese War ( 1547 – 49 ) The Burmese – Siamese War ( 1547 – 49 ) ( ; or สงครามพระเจ้าตะเบ็งชเวตี้ , lit . " Tabinshwehti ' s 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 . But the Burmese negotiated a safe retreat in exchange for the return of two important Siamese nobles ( the heir apparent Prince Ramesuan , and Prince Thammaracha of Phitsanulok ) whom they had captured . The successful defense preserved Siamese independence for 15 years . Still , the 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 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 . During this period of tumult , Mingyinyo , 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 . In 1530 , Mingyinyo ' 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 – 39 , the upstart kingdom captured Hanthawaddy ' s capital Pegu ( Bago ) , and in May 1541 , Martaban ( Mottama ) and Moulmein ( Mawlamyaing ) . 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 . The boy ' s father was King Borommarachathirat IV , Chairacha ' s half - brother . The child - king was subsequently executed by his uncle . 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 . 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 Maha Sena , and replaced them with her favourites . 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 . 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 . Prince Thianracha was immediately invited to leave the Sangha and assume the throne as King Maha Chakkraphat . 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 . Tenasserim ( 1547 – 1548 ) . The war began in 1547 . The casus belli have been stated as an attempt by 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 6000 had occupied Tavoy ( Dawei ) in the Upper Tenasserim coast , which he considered his territory , by January 1547 . As frontiers in the pre - modern period were less defined and often overlapped , 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 ( 8000 army , 4000 navy ) led by Saw Lagun Ein , viceroy of Martaban , to take over Tavoy c . October / November 1547 . A joint land - naval attack on Tavoy drove out the Siamese forces led by the Lord of Kanchanaburi to lower Tenasserim . 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 . The invasion force would have been equipped with the conventional weapons of the day : swords , bow and arrows and spear s . The more elite members would also carry matchlocks or muskets . 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 ) . 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 4000 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 Burmese three 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 . 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 . The invasion initially met little resistance , as the Burmese forces were too large for the small guard posts around the border . Upon hearing of the Burmese invasion , Maha Chakkraphat mobilized his kingdom , then gathered his forces at Suphanburi , a town just west of Ayutthaya . When Tabinshwehti and his army arrived at the walled town of Kanchanaburi , they found it completely deserted . About a month into the invasion , mid - November 1548 , the King of Burma then continued his march eastward , capturing the villages of Ban Thuan , Kaphan Tru and Chorakhe Sam Phan . The Burmese continued their advance and captured the ancient town of Uthong as well as the villages of Don Rakhang and Nong Sarai and closing in on Suphanburi . When the Burmese attacked the town , Siamese defenders could not withstand the onslaught and retreated towards Ayutthaya . Tabinshwehti ordered his army southeast along two canals , and crossed the Chao Phraya river near Phong Phaeng . From here he encamped his army directly north of the Siamese capital of Ayutthaya on a field called the Lumpli plain . Battle of Ayutthaya . At the outskirts . Maha Chakkraphat decided to leave the capital with his forces , to engage Tabinshwehti and test the Burmese strength . On this occasion , he mounted his chief war elephant . Accompanying him were his Chief Queen , Sri Suriyothai , and one of their young daughters , Princess Boromdhilok , the two riding together on a smaller war elephant . Both royal ladies were dressed in male military attire ( helmet and armour ) , with the queen wearing the uniform of an Uparaja . Also accompanying their father on elephant mounts were two sons , the Uparaja and heir apparent , Prince Ramesuan , and his brother Prince Mahin . A battle certainly ensued although there are naturally two accounts as to what actually took place . According to the Burmese chronicles , the Burmese command fielded an army led by Thado Dhamma Yaza , the Viceroy of Prome , as a decoy and the two armies lurked on the flanks in order to encircle any overstretched Siamese forces . As planned , the Siamese vanguard troops pressed on Thado Dhamma Yaza ' s army , allowing Bayinnaung ' s army waiting on the left flank to encircle the Siamese forces , which subsequently were wiped out . Tabinshwehti ' s army on the right flank drove back the remaining Siamese forces into the city . According to Thai tradition , however , Thado Dhamma Yaza and Maha Chakkraphat engaged in single elephant - combat , as was the custom of the time . But Maha Chakkraphat ' s elephant panicked and gave flight , charging away from the enemy ; Thado Dhamma Yaza swiftly gave chase . Fearing for the life of her husband , Queen Sri Suriyothai charged ahead to put her elephant between the King and the Viceroy , thereby blocking his pursuit . The Viceroy then engaged the Queen in single combat , fatally cleaving her from shoulder to heart with his spear , also wounding her daughter — both mother and child met their deaths on the back of the same elephant . It is said that the Viceroy did not know he was fighting a woman until his blow struck — as she fell dying her helmet came off , exposing her long hair . Prince Ramesuan and Prince Mahin then urged their elephants forward to fight the Viceroy , drove him and his remaining forces from the field , then carried the bodies of their mother and sister back to Ayutthaya . The Siamese king meanwhile rallied his army , and retreated in good order back towards the capital . The Burmese chronicles however do not mention any instance of single combat ( on elephant - back or otherwise ) by the viceroy of Prome . At any rate , the remaining Siamese forces retreated . Tabinshwehti readied his army for a siege of the Siamese capital . He made his camp north of the city , with his headquarters at Klum Dong , and had his commanders encamp in strategic places surrounding the city walls , Bayinnaung at Phaniat , the Viceroy at Ban Mai Makham , and the Governor of Bassein at the plain of Prachet . The Burmese would not , however , take the Siamese capital so easily . Siege . Ayutthaya sat on an island surrounded by three rivers — the Lopburi River to the north , the Chao Phraya River to the west and south , and the Pa Sak River to the east , forming a formidable natural moat . The Chao Phraya basin where Ayutthaya is situated was low and prone to flooding — especially intense during the rainy season when torrential waters flowed in great quantity from the north along the Lopburi River . This flood would begin approximately in July and end somewhere between October and November , giving Tabinshwehti only five months to capture Ayutthaya — otherwise his camp grounds and supply routes would be flooded . There was also the possibility that the flood could trap his forces . The low , swampy area around the city was laced with numerous canals thronging with gun boats armed with cannon to repulse any attempt at an attack on the city . Also , the Burmese had only small cannon that they had brought with them , while the Siamese had large cannon mounted along the city walls . The Burmese had the city surrounded , but without the ability to cross the rivers or breach the city walls with cannon fire , were left to camp around it instead , while the interconnected waterways to the north and south made it fairly easy to resupply the defenders in the city . Fifty Portuguese mercenaries , who had elected Galeote Pereira as their captain , defended the weakest part of the city wall for Maha Chakkraphat . Unable to take the city conventionally , Tabinshwehti offered bribes to these defenders . The Portuguese reacted with derision , and refused . When a Siamese commander heard of this , he swung open the gates of the city and dared the Burmese King to bring the money — a dare that was ignored . Maha Chakkraphat , being unable to repel the Burmese , sent a message to his son - in - law Maha Thammaracha at Phitsanulok , ordering his vassal to come to his aid by bringing an army southwards towards Ayutthaya and if possible to engage the enemy in battle . Thammaracha quickly mobilized his forces and with the help of the Governor of Sawankhalok , marched southward with a large army to attack the Burmese rear . Upon hearing of this and on the advice of Bayinnaung ; Tabinshwehti decided to withdraw , abandoning the mission altogether . His decision was compounded by news from Burma that the Mons , who had never been entirely subjugated by the Taungoo dynasty , rebelled in the absence of the king . Other factors included the scarcity of supplies and sickness in his army , which was not prepared for a long siege . Just one month into the siege , the Burmese command decided to withdraw . Retreat . Battle of Kamphaeng Phet . The Burmese forces chose to retreat via the Mae Lamao pass ( in modern day Mae Sot , Tak ) . In retreat , they tried to plunder the ancient and wealthy town of Kamphaeng Phet but the town was too well fortified . With the help of more Portuguese mercenaries , the Governor repelled the Burmese with flaming projectiles that forced the Burmese to cease using their cannons and protect them with coverings of damp hides . Maha Chakkraphat saw the Burmese army ' s retreat as an opportunity take advantage of their weakness , so he ordered Princes Ramesuan and Thammaracha to follow and harass the enemy out of Siamese territory . For three days , the Siamese chased the invaders , inflicting great losses upon them . Once the forces of Ramesuan and Thammaracha closed in , Tabinshwehti made a stand near Kamphaeng Phet , dividing his forces on both sides of the road . The Siamese in their eagerness fell into the trap . The Burmese captured both Prince Ramesuan and Maha Thammaracha as prisoners of war . Truce . The capture of his heir and his son - in - law forced Maha Chakkraphat to negotiate with Tabinshwehti . The Siamese at once sent emissaries bearing gifts , offering a peaceful retreat in return for the two princes . In exchange Maha Chakkraphat was forced to hand over to Tabinshwehti two prized male war elephants called Sri Mongkol ( ) and Mongkol Thawip ( ) . Once the elephants were handed over , the Burmese army retreated in peace . In addition to the two princes , Tabinshwehti also released many other prisoners he had captured during the campaign . According to the Burmese records , the Siamese king also agreed to provide an annual gift of 30 elephants , a token sum of money , and certain custom duties . After the treaty , the Burmese king rested for eight days , and returned to Pegu . He arrived back at Pegu on 1 March 1549 ( 3rd waxing of Late Tagu 910 ME ) . Aftermath . Despite his failure to take Ayutthaya , Tabinshwehti claimed to have regained control of the Tavoy frontier . Indeed , the Burmese chronicles claim the Siamese king had agreed to pay an annual tribute . Even if this claim was true , the Toungoo Dynasty ' s control over Tavoy lasted a little over a year in any case . Tabinshwehti was assassinated just a year after the Siamese campaign on 30 April 1550 , and the empire he had built in the previous 16 years quickly collapsed , with each town claiming a king . Even after Bayinnaung had restored the kingdom in the following years , the frontier region was likely under overlapping spheres of influence . It was only in 1562 that Bayinnaung made an emphatic claim by setting up a Burmese garrison at Tavoy , in preparation for his invasion of Siam a year later . Legacy . The war was the first of the many wars between Burma and Siam that would last well into the mid 19th - century . It was also the first time the city of Ayutthaya was actually attacked by a foreign enemy . The body of Queen Sri Suriyothai was placed at Suan Luang , the Royal Garden . Maha Chakkraphat ordered a grand cremation , and built a temple with a large stupa to house her remains . The temple , which still exists , is known as Wat Suan Luang Sop Sawan ( ) and the stupa is called Chedi Phra Sri Suriyothai ( ) . The temple and the stupa had been restored and rebuilt several times . Despite her stature among the Thais for her heroism , the historicity of her story and her existence has been the subject of debate . This is based on the fact that the queen is not mentioned in either the recorded or popular history of Myanmar . All the facts pertaining to her life were taken from fragments of the Siamese royal chronicle the " Annals of Ayutthaya " and an account by Domingos Seixas , a Portuguese explorer . The war led to the strengthening of Ayutthaya ' s defences , such as stronger walls and forts . A census of all able - bodied men was taken , as well as a massive hunt for wild elephants for use in future wars . The size of the navy was also increased . The Siamese success at repelling the Burmese would not be repeated . This first ever invasion gave the Burmese an important experience on fighting with Siamese . The next invasion would be conducted by Bayinnaung , a man accustomed to fighting against Siamese soldiers and familiar with marching through Siamese terrain . The unrest in Burma delayed that next invasion for fifteen years , until the War of 1563 or the War of the White Elephants . Media . The war beginning with the death of Chairacha was dramatized in the 2001 Thai historical drama " The Legend of Suriyothai " , directed by Mom Chao Chatrichalerm Yukol . The film portrays the events leading up to the war and the battles including the death of Queen Sri Suriyothai . The film cost an estimated 350 million baht , and is the highest budget Thai film . The film was released in the United States in 2003 . The succession crisis Ayutthaya is portrayed in the 2005 English language Thai film " The King Maker " . The film ends prior to the Burmese invasion .