The siege of Ayutthaya in 1766–1767, also known as the Fall of Ayutthaya and Sack of Ayutthaya, was a part of the Burmese–Siamese War (1765–1767), in which King Hsinbyushin of the Burmese Konbaung dynasty sent his generals Maha Nawrahta and Ne Myo Thihapate to conquer the Siamese Kingdom of Ayutthaya. After conquering and subjugating Siamese peripheral cities, the two Burmese invading columns converged onto and reached the royal city of Ayutthaya in January 1766. Unable to halt Burmese advances at the frontiers, the Siamese were obliged to take defensive positions in the fortified city of Ayutthaya.
By February 1766, the Burmese laid siege to Ayutthaya and approached the city walls of Ayutthaya city in September. Ayutthaya employed traditional defense strategies by relying on the supposed impregnability of its walls and the incoming of floods during the rainy season. The Burmese, however, circumvented these strategies by persisting to stay during the rainy season and by employing the tactics of destroying the bases of the city wall of Ayutthaya. After fourteen months of enduring the siege, the centuries-old royal Siamese capital of Ayutthaya fell to the Burmese on 7 April 1767 and was completely destroyed, signifying the end of the Ayutthaya kingdom and paving the way for subsequent events in Thai history.
Background
Burmese conquest of Siamese peripheral cities
During the Burmese invasion of Siam in 1765, King Hsinbyushin had sent his armies into Siam in pincer movement attacks to converge on Ayutthaya through two routes;
- A Tavoy column under Maha Nawrahta with 20,000 men, leaving Ava in December 1764 and stationing at Tavoy on the Tenasserim coast. The Tavoy column attacked and conquered the Siamese-held Mergui and Tenasserim in January 1765. In early 1765, a vanguard portion of the Tavoy column invaded Western Siam and conquered most of the cities including Ratchaburi, Suphanburi, Phetchaburi, Kanchanaburi, Kuiburi, Pranburi and Chumphon. King Ekkathat sent Siamese royal forces in an attempt to halt the Burmese at the Western frontiers but they failed and were defeated. Western Siamese people either took refuge in the forests or went into the service of the Burmese military. Regiments of Western Siamese war captives were raised to join Burmese service under the command of Mingyi Kamani Sanda. Maha Nawrahta marched his main armies from Tavoy crossing the Myitta Pass in November 1765 to station in Kanchanaburi. Maha Nawrahta then sent his forces to conquer Thonburi and Nonthaburi at the lower reaches of Chao Phraya River – the gateways of Ayutthaya to the sea. In the Battle of Nonthaburi in December 1765, a fierce battle ensued as the British merchant William Powney, in his assistance of Siam, inflicted heavy cannon fires on the Burmese at Nonthaburi. The Burmese at Nonthaburi retreated but when Siamese forces entered Nonthaburi unsuspectingly, the Burmese, in turn, ambushed and routed the attackers. After the Burmese victory at Nonthaburi, from Kanchanaburi, Maha Nawrahta divided his armies into two routes;
- Maha Nawrahta himself would march his land armies to approach Ayutthaya in the west.
- Mingyi Kamani Sanda, the naval commander, would sail his riparian fleet upstream the Chao Phraya River to approach Ayutthaya from the south.
- Hsinbyushin sent Ne Myo Thihapate, whose mother was a Lao-Lanna woman according to Thai chronicles, to lead Burmese armies of 20,000 men to subjugate the rebellious Lanna in February 1764. Nemyo Thihapate pacified the Lanna rebels against Burma and continued to attack and conquer the Lao Kingdom of Luang Phrabang in early 1765. The subjugation of Lanna and Laos added a large number of manpower to Burmese ranks and resources to the Burmese granary. This became the Lanna Chiang Mai regiment under the command of Nemyo Thihapate. Combined with new Lanna-Lao recruits, Nemyo Thihapate possessed up to 43,000 men in his armies. Ne Myo Thihapate left Lanna to descend on Northern Siam in mid-1765. The Northern Siamese cities of Phitsanulok, Sukhothai, Sawankhalok, Kamphaeng Phet, Tak, Nakhon Sawan and Ang Thong all fell to Burmese conquests in succession. Regiments of surrendered Northern Siamese people were raised to join the Burmese ranks.
Battle of the outskirts
The Burmese approached Ayutthaya from three directions;
- Maha Nawrahta and his Burmese Tavoy contingent approached Ayutthaya from the west through Suphanburi, stationing at Siguk (modern Bang Ban, Ayutthaya) around ten kilometers to the west of Ayutthaya.
- Nemyo Thihapate and his Burmese-Lanna armies approached Ayutthaya from the north, stationing at Paknam Prasop (modern Bang Pahan) about seven kilometers to the north of Ayutthaya.
- Mingyi Kamani Sanda and his Burmese fleet sailed upstream on the Chao Phraya to approach Ayutthaya from the south, settling in Bangsai (modern Bang Pa-in) to the south of Ayutthaya.
King Ekkathat sent Siamese armies to the north and the west in attempts to prevent the Burmese from taking position in the outskirts of Ayutthaya. Maha Nawrahta met with the Siamese commander Phraya Phollathep at Siguk in early 1766, leading to the Battle of Siguk. Maha Nawrahta ultimately prevailed and the Siamese retreated. At the northern front, Ekkathat sent Chaophraya Phrakhlang, the Siamese Prime Minister, to lead an army of 10,000 men to halt Nemyo Thihapate. In January 1766, Nemyo Thihapate met Phrakhlang at about two and a quarter miles to the northwest of Paknam Prasop, where Thihapate inflicted a humiliating defeat on the Siamese under Phrakhlang. Nemyo Thihapate reached the outskirts of Ayutthaya on 20 January 1766 (5th waxing of Tabodwe 1127 ME). In late January 1766, Ekkathat sent another army under Phraya Phetchaburi Rueang and Phraya Tak (future King Taksin) to dislodge Maha Nawrahta at Siguk. Maha Nawrahta sent his commanders Nemyo Gonnarat and Mingyi Zeyathu to meet the Siamese at Wat Phukhaothong temple, which was built by the Burmese king Bayinnaung two centuries earlier, to the northwest of Ayutthaya, leading to the Battle of Wat Phukhaothong. The Burmese were nearly routed but managed to catch up and turn the tide of the battle. The Siamese were again defeated and retreated into the fortified city of Ayutthaya.
Siamese preparations
Siamese defensive strategy
Manpower control inefficiencies crippled the Siamese defense capabilities. Effective manpower mobilization and strong military leadership of the times of King Naresuan in the late sixteenth century were not used. Peripheral governors had been deprived of their military prowess thus they were prone to rebellions. When the Burmese invaded again in 1765, King Ekkathat sent Siamese forces to halt the Burmese advances at the frontiers but to no avail, they were all defeated. Siamese commanders were inexperienced and lacking in strategies compared to their war-hardened Burmese counterparts. Ayutthaya did not care to hold outlying cities against the Burmese. The Siamese court recruited and called forces from the peripheral cities, including their governors, to defend Ayutthaya city. This left the periphery even less defended as western and northern Siamese towns fell prey to Burmese conquests in rapid succession.
With the Burmese victories at Paknam Prasop and Wat Phukhaothong in January 1766, they were able to set foot on the Ayutthayan outskirts to lay siege to the Siamese royal city by February. Defeated many times, Siam had no choice but to resort to traditional defensive strategies. Siam evacuated all people from the suburbs into the city, shut the city gates tight and put up defenses. This strategy relied on the supposed impregnability of Ayutthaya's city walls and the arrival of the Siamese wet season.
Ayutthaya City Walls
The Ayutthaya city is situated on an island at the confluence of three rivers – namely Chao Phraya, Lopburi and Pasak, surrounded by the waters serving as a natural city moat. The first wall erected at the foundation of Ayutthaya in 1350 was a simple earthen wall. With the inception of the Burmese–Siamese wars, King Maha Chakkraphat built new walls from brick and stones to replace the old earthen wall in 1550. Maha Chakkraphat also constructed two main forts of Pomphet and Satkop. King Maha Thammaracha expanded the city walls to fully reach the eastern riverbanks in 1580. The Ayutthayan city walls had stood against Burmese attacks in 1564, 1569, 1587, 1760 and two Cambodian attacks in 1570 and 1578. The walls then stood for two centuries with limited usage and several renovations. Western engineers contributed to a more sturdy, reinforced style of the wall. After 1586, no invaders had reached Ayutthaya city for nearly two hundred years until 1760.
The Ayutthaya city walls stood three wa and two sok (seven meters) in height with two wa (about four meters) in thickness. It had up to sixty regular city gates with about twenty large tunnel gates that allowed large groups of people or domesticated animals to pass. It also had water gates that facilitated transport by boat. The gates were decorated with flared crosspieces at the top similar to the Giant Swing in modern Bangkok and were designed to impress rather than to keep enemies out. There were sixteen surrounding forts embedded into the walls. The three most important fortresses of Ayutthaya located at strategic centers were;
- Pomphet Fort or Diamond Fort, located at the confluence of Chao Phraya and Pasak rivers at the southeastern corner of Ayutthaya city, constructed in 1550, was the most important defense fort on the southern side of Ayutthaya city wall. It was the point where all foreign ships, according to Siamese law, were unloaded and inspected. All ships passing into Ayutthaya city had to go through this point.
- Mahachai Fort, located at the junction of the Lopburi and Pasak rivers at the northeastern corner, constructed in 1580, protected against invaders coming from the east.
- Satkop Fort, located at the interception of Chao Phraya and Lopburi rivers at the northwestern corner, protected against invaders from the west.
Siamese armory
Ayutthaya had plenty of firearms and cannons. Siam had learned the production of matchlock firearms and bronze cannons from the Portuguese in the sixteenth century. Siam had domestic furnaces for cannon casting and became a renowned manufacturer of cannons. Two cannons gifted by King Narai to King Louis XIV of France in 1686 ended up being used by French revolutionaries during the storming of Bastille in 1789. However, both Burma and Siam were unable to produce their own flintlock muskets – a new technology that had to be exclusively imported from the Europeans. Siam used their wealth to acquire several thousand muskets and artillery guns. The Siamese government purchased a large number of Western-produced, cast-iron, larger-caliber cannons known in Thai as "Bariam" (from Malay Meriam). Individual cannons were religiously worshipped by the Siamese for they believed supernatural protector spirits resided in those cannons. Siam also utilized small-caliber breechloader cannons that were employed in hundreds on the battlefield and could also be mounted on elephants or ships.
Even though Ayutthaya possessed a large number of firearms, during the Burmese invasion of 1765–1767, they were not utilized to their full potential. A long hiatus from warfare meant few Siamese were skilled in effectively operating these firearms. Thai chronicles reveal that Siamese cannoneers mishandled their own cannons, missing the targets. Some cannons were left out of maintenance and became non-functional during wartime. Meanwhile, the Burmese put emphasis on marksmanship training to inflict the greatest damage to their enemies. In 1759, King Alaungpaya issued a royal decree instructing his musketeers on how to properly use flintlock firearms. It is estimated that sixty percent of Burmese military personnel operated flintlock muskets.
Wet rainy season
In pre-modern times, Burmese–Siamese wars were conducted in the dry season between January and August of each year. The rainy season arrived in May and the waters began to rise in September, when downflowing water from northern regions combined in the central river plain. The island with the city of Ayutthaya itself was situated on high grounds and not susceptible to the seasonal floods. However, the outlying areas of Ayutthaya became inundated and turned into a vast sea of flood water during the wet season. The water level peaked in November. Any invaders were obliged to leave Ayutthaya at the advent of the flood season as high water levels would cripple any battle. Military personnel would could not camp in flood zones and provisions would be damaged. Flooded swamps also bore diseases.
None of the earlier Burmese invaders had remained during the notorious Siamese flood season. Even the great Burmese king Bayinnaung abandoned his conquest of Ayutthaya at the arrival of the wet season in 1569. King Ekkathat reasoned that the Burmese would eventually retreat at the end of dry season. However, the Burmese had other plans and did not intend to leave. King Hsinbyushin had planned his campaign to conquer Siam to possibly span many years, and was not deterred by the rainy season.