Siege of Bangkok The Siege of Bangkok was a key event of the Siamese revolution of 1688 , in which the Siamese people ousted the French from Siam . Following a coup d ' état , in which the pro - Western king Narai was replaced by Phetracha , Siamese troops besieged the French fortress in Bangkok for four months . The Siamese were able to muster about 40 , 000 troops , equipped with cannon , against the entrenched 200 French troops , but the military confrontation proved inconclusive . Tensions between the two belligerents progressively subsided , and finally a negotiated settlement was reached allowing the French to leave the country . The Siege of Bangkok would mark the end of French military presence in Siam , as France was soon embroiled in the major European conflicts of the War of the League of Augsburg ( 1688 – 1697 ) , and then the War of the Spanish Succession ( 1701 - 1713 / 1714 ) . With the end of the siege , a long period started during which Siam would remain suspicious of Western intervention . Only a few French missionaries were allowed to remain , while trade continued on a limited level with other European countries such as Holland and England . Background . King Narai had sought to expand relations with the French , as a counterweight to Portuguese and Dutch influence in his kingdom , and at the suggestion of his Greek councilor Constantine Phaulkon . Numerous embassies were exchanged in both directions , including the embassy of Chevalier de Chaumont to Siam in 1685 and the embassy of Kosa Pan to France in 1686 . This led to a major dispatch of French ambassadors and troops to Siam in 1687 , organized by the Marquis de Seignelay . The embassy consisted of a French expeditionary force of 1 , 361 soldiers , missionaries , envoys and crews aboard five warships . The military wing was led by General Desfarges , and the diplomatic mission by Simon de la Loubère and Claude Céberet du Boullay , a director of the French East India Company . Desfarges had instructions to negotiate the establishment of troops in Mergui and Bangkok ( considered as " the key to the kingdom " ) rather than the southern Songkla , and to take these locations if necessary by force . King Narai agreed to the proposal , and a fortress was established in each of the two cities , which were commanded by French governors . Desfarges noted in his account of the events that he was in command of the fortress of Bangkok , with 200 French officers and men , as well as a Siamese contingent provided by King Narai , and Du Bruant was in command of Mergui with 90 French soldiers . Another 35 soldiers with three or four French officers were assigned to ships of the King of Siam , with a mission to fight piracy . The disembarkment of French troops in Bangkok and Mergui led to strong nationalist movements in Siam directed by the Mandarin and Commander of the Elephant Corps , Phra Phetracha . By 1688 anti - foreign sentiments , mainly directed at the French and Phaulkon , were reaching their zenith . The Siamese courtiers resented the dominance of the Greek Phaulkon in state affairs , along with his Japanese wife Maria Guyomar de Pinha and European lifestyle , whilst the Buddhist clergy were uneasy with the increasing prominence of the French Jesuits . The Siamese mandarinate under the leadership of Phetracha complained about the occupation force and increasingly opposed Phaulkon . Matters were brought to a head when King Narai fell gravely ill in March 1688 . Phetracha initiated the Siamese revolution of 1688 by seizing the Royal Palace in Lopburi and putting king Narai under house - arrest on May 17 – 18 . He also imprisoned Constantine Phaulkon on May 18 , 1688 , and executed the king ' s adopted son Mom Pi on May 20 . General Desfarges in Lopburi . On June 2 , General Desfarges , commander of the Bangkok fortress , was invited to Lopburi by Phetracha , and according to the account of one of his officers named De la Touche received promises of significant personal gains , such as the naming of his eldest son , Marquis Desfarges , to a major position in the Siamese government , equivalent to that which Constantine Phaulkon had held . Phetracha also required Desfarges to move his troops from Bangkok to Lopburi in order to contribute in an ongoing war with the Lao and the Cochin - Chinese . Desfarges managed to leave by promising that the would send the troops demanded by Phetracha , and that he would remit the fortress of Bangkok . He also had to leave his two sons as hostages to Phetracha . Desfarges left Lopburi on June 5 . As Desfarges had shown no interest in the fate of Phaulkon , Phetracha ordered Phaulkon ' s execution the same day . Phaulkon , who had been submitted to many tortures since his arrest , was beheaded by Phetracha ' s own son , Ok - Phra Sorasak . Desfarges returned to Bangkok on June 6 , accompanied by two mandarins , including Kosa Pan , the former ambassador to France , to whom he was supposed to remit the fortress . According to Vollant de Verquains , on that same day , in a council of war with his officers , the decision was taken not to obey Phetracha , but rather to resist him and start an armed confrontation . Start of the hostilities . Phetracha moved to besiege the French fortress in Bangkok with 40 , 000 men , and over a hundred cannon . The Siamese troops apparently received Dutch support in their fight against the French , and the Dutch factor Johan Keyts was accused of collaborating with the Siamese . The French had two fortresses ( one in Bangkok , one in Thonburi on the other side of the Chao Phraya river ) and 200 men , including officers . General Desfarges was commander - in - chief , and Mr de Vertesalle was second in command . For food , they also had about 100 cows , which Constance Phaulkon had had the foresight of providing them , which they started to slaughter . In order to facilitate defensive work , they also burnt down the small village which was near the Bangkok fortress . The first act of war was the attack on a Chinese junk belonging to the king of Siam , which was passing by . The captain of the junk had refused to give supplies to French , especially the salt which was needed to salt meat , and therefore was fired on repeatedly . Thonburi fortress . The French initially occupied both sides of the Chao Phraya in Bangkok , with two fortresses , one on the left bank ( the Bangkok fortress ) and one on the right bank ( the Thonburi fortress ) . Seeing that the position would be difficult to defend , especially since communications would become nearly impossible at low tide , the French decided to regroup in the larger fortress , on the left bank of the river . The French destroyed parts of the fortifications , split 18 cannons and spiked the rest . Soon after they left the smaller fort , Siamese troops invested it and began to set up cannons and mortar s to bombard the French positions . Forty cannons were set up there , which were in a very good position to shoot at the French fortress on the other side of the river . As the Siamese were using the Thonburi fortress advantageously , the French decided to launch an attack against it and destroy it . A detachment of 30 men was sent , on two longboats led by an ensign . The French were overwhelmed by the Siamese forces , however , and although several had managed to scale the ramparts , they soon had to jump from it . Four French soldiers were killed on the spot , and four later died from their wounds . Siamese encirclement of the Bangkok fortress . The Siamese then endeavored to confine the French troops in the Bangkok fortress , by building redoubt s . Twelve small forts were constructed around the French fortress , each one containing between seven and ten cannons . According to the French , this was done with the help of the Dutch . The Chao Praya , connecting the fortress of Bangkok to the sea , was lined with numerous forts , and was blocked at its mouth with five to six rows of huge tree trunks , an iron chain and numerous embarkations . Altogether , there were seven batteries , containing 180 cannons . Since two ships of the king of Siam were out at sea being commanded by some of his officers , Desfarges sent a longboat to try to reach them , and possibly call the French in India ( Pondicherry ) for help . The longboat was commanded by a company lieutenant and ship ensign , Sieur de Saint - Christ . He was blocked on his way to the sea , however , as numerous fortifications and Siamese soldiers had been established there . Overwhelmed , Saint - Christ self - exploded his own ship , leading to the death of hundreds of Siamese and most of the French crew except two , who were ultimately remitted to Desfarges . De - escalation and peace . In an effort to end the stalemate with the French in Bangkok , on June 24 Phetracha released the two sons of Desfarges , whom he had been holding as hostages since the visit of General Desfarges to Lopburi in early June , as well as all other French prisoners . Although he tried to make peace with the French , Phetracha managed to eliminate all the viable candidates to the throne : the two brothers of the king were executed on July 9 , 1688 . King Narai himself died on July 11 , possibly with the help of poisoning . Phetracha was crowned king on August 1 , 1688 , in Ayutthaya . He founded the new " Ban Phlu Luang " dynasty . After that time , the tension around the French in Bangkok subsided , with fewer cannon shots being traded , and exchanges of food and services being resumed to a certain level . Some discussions were also cautiously started to find an agreement . On September 9 , the French warship " Oriflamme " , carrying 200 troops and commanded by de l ' Estrilles , arrived at the mouth of the Chao Phraya River , but was unable to dock at the Bangkok fortress as the entrance to the river was being blocked by the Siamese . According to Vollant des Verquains , this put further pressure on the Siamese however to find a peaceful way out of the conflict . Desfarges finally negotiated in the end of September 1688 an agreement to leave the country with his men on board the " Oriflamme " and two Siamese ships , the " Siam " and the " Louvo " , provided by Phetracha . The new king Phetracha gave back all his French prisoners . To guarantee the agreement , the French were supposed to leave the country holding two Siamese hostages , while three French hostages were supposed to remain in Siam until the Siamese ships were returned : Mgr Laneau , Bishop of Metellopolis , Véret , the head of the French factory in Siam , and Chevalier Desfarges , the younger son of General Desfarges . Maria Guyomar de Pinha . Phaulkon ' s Catholic Japanese - Portuguese wife , named Maria Guyomar de Pinha , who had been promised protection by being ennobled a countess of France , took refuge with the French troops in Bangkok , where she was able to stay from October 4 – 18 , 1688 . She had managed to flee Ayutthaya with the help of a French officer named Sieur de Sainte - Marie . According to Desfarges himself , Phetracha demanded her return , threatening to " abolish the vestiges of the ( Christian ) religion " , and he further captured dozens of French people to obtain her return : the Jesuit Father de La Breuille , 10 missionaries , fourteen officers and soldiers , six members of the French East India Company , and fourteen other French people ( including three ship captains , three mirror technicians , Sieur de Billy , governor of Phuket , a carpenter named Lapie , and the musician Delaunay ) . Desfarges , afraid of compromising the peace agreement and resume a full conflict , returned her to the Siamese on October 18 , against the opinion of his officers . Despite the promises that had been made regarding her safety , she was condemned to slavery in the kitchens of Phetracha , which remained in effect until Phetracha died in 1703 . Retreat from Bangkok . Desfarges finally left with his men to Pondicherry on November 13 , on board the " Oriflamme " and two Siamese ships , the " Siam " and the " Louvo " , provided by Phetracha . Altogether , the siege had lasted more than four months , until the negotiated settlement was reached . Of the three French hostages who were supposed to remain in Siam until the Siamese ships were returned , only Mgr Laneau , Bishop of Metellopolis , actually remained , while Véret , the head of the French factory , and the Chevalier Desfarges , son of the General , managed to flee on board the " Oriflamme " . The Siamese , angered by the non - respect of the agreement , seized some of the French baggage , about 17 remaining French soldiers , and put Mgr Laneau in prison for several years . On November 14 , the day following the departure of the French , the 1644 Treaty and Alliance of Peace between Siam and the Dutch East India Company ( VOC ) was renewed , guaranteeing the Dutch the deerskin export monopoly they had had , and giving them freedom to trade freely in Siamese ports with anyone . They also obtained a renewal of their export monopoly on Ligor for tin ( originally granted by king Narai in 1671 ) . The Dutch , and to lesser extent the English , continued to trade in Ayutthaya , although with difficulty . Aftermath . Once arrived in the small French settlement of Pondicherry , some of the French troops remained to bolster the French presence there , but most left for France on February 16 , 1689 aboard the French Navy " Normande " and the French Company " Coche " , with the engineer Vollant des Verquains and the Jesuit Le Blanc aboard . The two ships were captured by the Dutch at the Cape of Good Hope , however , because the War of the Augsburg League had started . After a month in the Cape , the prisoners were sent to Zeeland where they were kept at the prison of Middelburg . They were able to return to France through a general exchange of prisoners . On April 10 , 1689 , Desfarges – who had remained in Pondicherry – led an expedition to capture the tin - producing island of Phuket in an attempt to restore some sort of French control in Siam . The island was captured temporarily in 1689 , but the occupation led nowhere , and Desfarges returned to Pondicherry in January 1690 . Recalled to France , he left 108 troops in Pondicherry to bolster defenses , and left with his remaining troops on the " Oriflamme " and the Company ships " Lonré " and " Saint - Nicholas " on February 21 , 1690 . Desfarges died on his way back trying to reach Martinique , and the " Oriflamme " later sank on February 27 , 1691 , with most of the remaining French troops , off the coast of Britanny . France was unable to stage any comeback or organize a retaliation due to its involvement in major European conflicts : the War of the League of Augsburg ( 1688 – 1697 ) , and then the War of the Spanish Succession ( 1701 - 1713 / 1714 ) . France only resumed official contacts in 1856 , when Napoleon III sent an embassy to King Mongkut led by Charles de Montigny .