Prince Kromma Muen Thepphiphit (Thai: กรมหมื่นเทพพิพิธ) was a Siamese prince of the Ban Phlu Luang dynasty of the Ayutthaya kingdom. He is known for his colorful adventurous political career.^[1]: 208 Prince Thepphiphit led a failed rebellion in 1758 against his half-brother Ekkathat^[1]: 208 the last king of Ayutthaya. He was then exiled to Ceylon, which had been under the Kingdom of Kandy. In 1760, Sinhalese Sangha and nobility conspired to overthrow King Kirti Sri Rajasinha of Kandy to place the Siamese prince Thepphiphit on the Kandyan throne but the plan was thwarted and Thepphiphit had to leave Ceylon. Prince Thepphiphit returned to Siam at Mergui, Tenasserim, in 1762. When the Burmese attacked and conquered Tenasserim in early 1765, Thepphiphit moved to Chanthaburi on Eastern Siamese coast. In 1766, he raised an army in Eastern Siam to fight the Burmese but was defeated. Thepphiphit fled to Nakhon Ratchasima in the northeast where he engaged in a local power struggle, ending up being held hostage at Phimai. At the fall of Ayutthaya in 1767, local officials in the northeast declared Thepphiphit a ruler, becoming "Chao Phimai" or the Lord of Phimai as one of several regional regime leaders in aftermath of the collapse of Ayutthaya, entrenching himself at Phimai.^[2]: 34 In 1768, the new king Taksin of Thonburi kingdom marched to subjugate Thepphiphit's Phimai regime. Thepphiphit was then captured and deported to Thonburi, where he was eventually executed^[3]: 264 in November 1768.

Very few native Siamese records about the early life of Prince Thepphiphit survive. A Chinese source stated that, at his death in 1768, Prince Thepphiphit was around fifty years old^[4] so he should be born around 1718, in the reign of his uncle King Thaisa of Ayutthaya. Prince Thepphiphit, at his birth, was known as Khaektao ("parakeet") or Prince Phra Ong Chao Khaek (Thai: พระองค์เจ้าแขก) of the Phra Ong Chao rank. The Chinese source stated that Thepphiphit was an elder half-brother of Ekkathat,^[4] who was also born in 1718, while in Thai chronicles the order of the princes was given as Prince Thammathibet coming as the first one, Ekkathat as the second one and Thepphiphit as the third one. Thepphiphit should be nearly the same age as his half-brother Ekkathat.

Prince Thepphiphit, initially known as Prince Khaek, was a son of Prince Phon, who was the younger brother and Wangna or Uparat or heir presumptive to King Thaisa. He was born to an unnamed secondary consort of his father. According to the Chinese source, Thepphiphit's mother was of the Baitou race,^[4] suggesting Northern Thai or Lao ethnicity. Thepphiphit had a younger brother Prince Phra Ong Chao Pan (Thai: พระองค์เจ้าปาน) and a sister who shared the same mother. In 1732, King Thaisa became ill and Prince Phon, Thepphiphit's father, rallied armies in preparation for the upcoming succession conflict^[1] but was caught. Prince Phon, along with his sons and presumably Thepphiphit, ordained as Buddhist monks^[1] to avoid political repurcussions. Next year, in 1733, King Thaisa died and a succession war ensued in Ayutthaya between Prince Phon and his nephews, sons of Thaisa. Prince Phon eventually prevailed and ascended the Siamese throne as King Borommakot in 1733.

In efforts to contain future dynastic princely conflicts, King Borommakot assigned manpower regiments known as Kroms^[1] to his sons the royal princes to control the allocation of manpower among his sons. Prince Khaek was given the Krom title Kromma Muen Thepphiphit (Thai: กรมหมื่นเทพพิพิธ), while his brother Prince Pan became Kromma Muen Sepphakdi (Thai: กรมหมื่นเสพภักดี). Borommakot's sons were also ranked according to the status of their mothers. Thammathibet, Ekkathat and Uthumphon, who were born to Borommakot's two main queens, were given the superior rank of Kromma Khun. Other sons of Borommakot who were born to his secondary consorts, including Thepphiphit and his brother Sepphakdi, were given the inferior rank of Kromma Muen.^[1]: 200

Prince Thammathibet, eldest son of Borommakot born to a principal queen, was made Wangna Prince of the Front Palace and heir presumptive to Borommakot in 1741.^[1]: 200 The princes maintained uneasy share of power during the reign of their father. The seven royal princes were divided into two political camps.^[1] The first faction composed of primary sons of Borommakot including Thammathibet, Ekkathat and Uthumphon. The second faction composed of the secondary princes including Chitsunthorn, Sunthornthep and Sepphakdi^[1] (Thepphiphit's brother), known collectively as Chao Sam Krom (Thai: เจ้าสามกรม) or the Three Princes. Thepphiphit, despite being a secondary prince, seemed to be aligned with the faction of the superior princes. Death of Chaophraya Chamnan Borirak the Chief Minister in 1753 allowed Prince Thammathibet the royal heir to assert his powers. Prince Thammathibet was later found having adulterous relationship with a consort of his father Borommakot and was also found yearning for a sedition. Prince Thammathibet was whipped with rattan cane strokes and died from injuries in April 1756.^[1]

Death of Prince Thammathibet in 1756 left the position of royal heir vacant. It was this time that Prince Thepphiphit made his first political move. King Borommakot disfavored his second son Ekkathat for his supposed incompetency. Thepphiphit then led the propasal to the king in 1757, in concert with other high-ranking ministers of Chatusadom, to make Uthumphon the new heir. Uthumphon, as the youngest son of Borommakot, did not aspire for kingship but Borommakot preferred Uthumphon over Ekkathat, citing that Ekkathat would be sure to bring disaster to the kingdom.^[1] Uthumphon finally consented to the demands of his father Borommakot, who made Uthumphon the Prince of the Front Palace and heir presumptive in 1757 and also exiled Ekkathat to become a Buddhist monk in the northeastern outskirt of Ayutthaya to prevent Ekkathat from incurring any troubles. This event earned Thepphiphit a political favor as he was the one who proposed to Borommakot to elevate Uthumphon to the position.

In spite of these speculative arrangements, conflicts erupted between Uthumphon and the Three Princes who sought to claim the throne when Borommakot died in April 1758. Ekkathat returned from exile to assist Uthumphon in putting down the Three Princes. Ekkathat, Uthumphon and Thepphiphit unified and cooperated against the Three Princes. The Three Princes, including Thepphiphit's brother Sepphakdi, were eventually captured and executed in May 1758. Uthumphon triumphantly ascended the Ayutthayan throne in May but Uthumphon faced political challenges from Ekkathat who laid his own claims to the throne. Uthumphon gave in and abdicated after merely ten days.^[5]: 244 Ekkathat ascended the throne as the last king of Ayutthaya in June 1758, while Uthumphon went to become a Buddhist monk at Wat Pradu temple,^[6] earning him the epithet Khun Luang Hawat or the King Who Sought Temple.

With the ascension of Ekkathat at the expense of Uthumphon, Thepphiphit felt threatened because he had been such a supporter of Uthumphon. After the enthronement ceremony of Ekkathat, Thepphiphit went out in June 1758 to be ordained as a Buddhist monk^[1] to avoid possible political retributions from Ekkathat, staying at Wat Krachom temple just off the northeastern corner of Ayutthaya citadel.

Upon his ascension to the throne, Ekkathat found few supports in the royal court, most of whom supported Uthumphon. Ekkathat brought his two brother-in-laws Pin and Chim to power in Siamese royal court. Pin and Chim were given immense powers. They upset and insulted high-ranking Chatusadom ministers. Those ministers, including Chaophraya Aphairacha the Chief Minister and Phraya Yommaraj the Police Chief, conspired to overthrow Ekkathat in favor of Uthumphon. In December 1758, those conspirators visited Prince Thepphiphit, who had been a Buddhist monk at Wat Krachom temple. Thepphiphit, despite being a Buddhist monk, was still very active in politics. Thepphiphit accepted this challenge. Thepphiphit and other conspirators visited Uthumphon at Wat Pradu temple,^[6] asking Uthumphon to consent to the plan. Uthumphon, who was unwilling to be involved in such seditious affair, gave a vague unpromising answer^[6] that was interpreted as favorable by Thepphiphit.

Uthumphon, however, decided not to trust Thepphiphit, given his ambitions. Uthumphon told Ekkathat about the upcoming rebellion in exchange for Ekkathat sparing the lives of the conspirators. The conspiring ministers Aphairacha, Yommaraj and others were arrested, punished, whipped with rattan canes and improsoned^[6] for life but not executed. Thepphiphit himself fortified at Wat Krachom temple against Ekkathat. Thepphiphit's Chao Krom or Chief Servant managed to raise a number of supporters who vehemently and devotedly defended Thepphiphit. Ekkathat devised a plan to take down Thepphiphit without forces by declaring that the crime of sedition would be placed solely upon the Chao Krom or Thepphiphit's Chief Servant. The Chief Servant then deserted Thepphiphit along with his subordinates, leaving Thepphiphit exposed. Thepphiphit was left with no choices but to escape. Thepphiphit fled to the west where he was caught and apprehended at Phra Thaen Dong Rang in modern Tha Maka district, Kanchanaburi province.

Upholding the promise made to Uthumphon, Ekkathat would not execute Thepphiphit but rather exile him. Coincidentally, a Dutch ship happened to arrive in Ayutthaya to procure some Siamese Buddhist monks to Sri Lanka. Ekkathat then had Thepphiphit, still in Buddhist monk robes, along with his family, consorts and children, board on the Dutch ship across the Indian Ocean to be exiled to Ceylon or Sri Lanka^[1]: 209 in early 1759.

Ascension of King Sri Vijaya Rajasinha, who was of Southern Indian Telugu Nayakkar origin, to the Sinhalese throne of Kandy in 1739, with the support of his mentor the Sinhalese Buddhist monk Weliwata Sri Saranankara, began the rule of Madurai Nayak dynasty over Ceylon.^[7]: 139 The Nayaks of South India were practitioners of Shaivite Hinduism rather than Sinhalese Theravada Buddhism. In the aftermath of repeated Portuguese and Dutch incursions, Theravada Buddhism in Ceylon had been in a deteriorated state without any properly ordained Bhikkhu monks^[7] left to maintain and continue the religion.

King Sri Vijaya Rajasinha died in 1751 and was succeeded by his brother-in-law Kirti Sri Rajasinha.^[7]: 140 The new king Kirti Sri Rajasinha of Kandy, inspired by the monk Weliwata Saranankara, made efforts to rehabilitate Sinhalese Theravada by sending delegates to the Siamese kingdom of Ayutthaya, requesting for Siamese monk to revive the Upasampada ordinations and to reestablish Bhikkhu monastic order in Ceylon. King Borommakot of Ayutthaya responded by sending Siamese monks under Upali to Ceylon, arriving in 1753,^[7]: 141 leading to conception of the Siam Nikaya sect in Sri Lanka. The monk Weliwata Saranankara was ordained by the Siamese monks into this new 'Siamese sect'. Since then, Ayutthaya and Kandy had been maintaining religious relations, with Dutch ships serving as the conduit to regularly transport Siamese monks to Sri Lanka. Weliwata Saranankara was appointed by Kirti Sri Rajasinha in 1753 as the Sangharaja^[7] or Buddhist Hierophant in Sri Lanka. Despite these religious achievements, the powerful native Sinhalese monks, led by Weliwata Saranankara himself, were contemptuous at the king's association with Hinduism.

Thepphiphit arrived in Ceylon at the Dutch port of Colombo in 1759 in Buddhist monk robes on the Dutch ship along with his family. The Dutch source recorded Thepphiphit's monastic name as Tammebaan^[8] or Thammaban in Thai. The Sinhalese, who apparently did not know about the reason of Thepphiphit's arrival, provided Thepphiphit and his family with accommodation in Kandy. Arrival of Thepphiphit in Ceylon perhaps served as the catalyst for the imminent revolution against King Kirti Sri Rajasinha. Thepphiphit befriended a relative of the Sinhalese noble Sammanakodi the Udagampaha Adigar.^[8] In 1760, the Sangharaja Weliwata Saranankara conspired with Adigar Sammanakodi and the monks of the Siamese sect, including the Siamese monks themselves, to overthrow the Nayakkar King Kirti Sri Rajasinha and put the Siamese prince Thepphiphit on the throne of Kandy. The conspirators, including Thepphiphit himself, held a secret meeting at a temple in Anuradhapura to conceive the plan.^[8] Thepphiphit then went to stay at Kehelella^[8] near Colombo, waiting for the signal.

In 1760, Adigar Sammanakodi invited King Kirti Sri Rajasinha for a Buddhist sermon in Siamese language^[8] at the Malvatta temple, the head temple of the Siamese sect. In the same time, a message in Thai language was sent to Thepphiphit but the message was intercepted and sent to Kirti Sri Rajasinha.^[8] The king sent his men to the Malvatta temple of the monk Weliwata Saranankara where they found the apparatus to assassinate the king – a coffin with protruding spikes and a platform above it.^[8] It was assumed that the plan was for Kirti Sri Rajasinha to sit on the platform during the sermon, in which the platform would collapse, the king would fall into the coffin and impaled to death by the spikes. Conspirators were arrested. Adigar Sammanakodi was executed, while the Sangharaja monk Weliwata Saranankara was imprisoned in Kehelella. Siamese monks were expelled to the Dutch-controlled area.

Thepphiphit and his family then left Ceylon with Dutch assistance, presumably on a Dutch ship from Colombo. Thepphiphit stayed at the Dutch port of Tuticorin^[8] in South India for a while. In May 1761, the Chinese Annals of Batavia or Kai Ba Lidai Shiji (開吧歷代史記)^[9] stated that 'a son of the King of Ceylon and his wife' arrived in Batavia,^[9] where they were ceremoniously received by Dutch East Indies Governor-General Petrus Albertus van der Parra in the Batavia Castle.^[9] This enigmatic princely figure from Ceylon should be Prince Thepphiphit,^[9] who took shelter at Batavia after his troubled departure from Ceylon. The Dutch Governor-General provided Thepphiphit with residence in the Great Mauk.^[9]

Since the sixteenth century, Western powers the Portuguese and later the Dutch had taken control of all coastal lowlands of Ceylon, driving the indigenous power to the mountainous inland. After Kirti Sri Rajasinha of Kandy had averted the assassination attempt upon himself in 1760, in the same year, the Sinhalese people on the coastal lowlands under Dutch rule rebelled against the Dutch governor Jan Schreuder of Ceylon. Next year, in 1761, King Kirti Sri Rajasinha of Kandy took this opportunity to invade and conquer the coastal lowlands from Dutch Ceylon. Facing internal unrest and external incursion, Jan Schreuder was relieved from his position in 1762, replaced by Lubbert Jan van Eck.

One of the sons of Thepphiphit died during his journey from Ceylon back to Siam.^[1]: 258 Thepphiphit and his family returned to Siam at the Siamese port of Mergui in Tenasserim in 1762. King Ekkathat of Ayutthaya was shocked and furious at the return of Thepphiphit. Ekkathat sent a royal intendant to impose confinement on Thepphiphit at Tenasserim, not allowing Thepphiphit to return to Ayutthaya. Meanwhile, two sons of Thepphiphit were sent to live with Uthumphon the temple king at Wat Pradu temple in Ayutthaya as political hostages.^[1]: 258 His wives and daughter were also sent to Ayutthaya.

Lubbert Jan van Eck the Dutch governor of Ceylon, in his wars against King Kirti Sri Rajasinha of Kandy, decided that he needed a competing candidate against Kirti Sri Rajasinha to the throne of Kandy. In 1762, Van Eck sent his delegate Marten Huysvoorn^[1] to Ayutthaya to ask the Siamese king Ekkathat to allow Thepphiphit or any of his sons to return to Ceylon^[1] as a competing claimant against Kirti Sri Rajasinha. The Dutch, however, did not know about political enmity between the half-brothers Ekkathat and Thepphiphit. The idea that Ekkathat's renegade half-brother and political enemy becoming a sovereign king of a foreign kingdom was unthinkable. Ekkathat did not allow any royal audiences with Huysvoorn.^[1] There were even rumors that the Dutch would soon attack Ayutthaya to put Thepphiphit on the Siamese throne,^[1] while Thepphiphit was still being grounded in Tenasserim. After many failed lobbies, Huysvoorn eventually left Ayutthaya empty-handed.

Thepphiphit remained in confinement in Tenasserim for nearly three years, with his family in Ayutthaya, until things took yet another turn in 1765. In early 1765, the Burmese invaded and conquer the Siamese Tenasserim Coast. Mergui fell to the Burmese in January 1765. Thepphiphit had to hurriedly flee the Burmese onslaught through the Singkhon Pass into the Gulf of Siam coast. Ekkathat again sent intendant to bring Thepphiphit to confinement in the new place of Chanthaburi on Eastern Siamese coastline, far from Ayutthaya.

Thepphiphit remained obedient to his half-brother King Ekkathat of Ayutthaya until mid-1766 when the Ayutthayan defenders realized that the Burmese besiegers would not leave for the wet rainy season. Situation of Ayutthaya worsened in its stand against the besieging Burmese and people began to leave Ayutthaya for safety if possible. In mid-1766, Thepphiphit made another important political move by leaving his confinement in Chanthaburi and went to Prachinburi, where he rallied Eastern Siamese forces to fight the Burmese. Eastern Siamese men from Eastern Siamese towns including Prachinburi, Nakhon Nayok, Chacheongsao, Chonburi and Bang Lamung rallied to Thepphiphit's host at Prachinburi.

Thepphiphit managed to gather 2,000 Eastern Siamese men and built himself a stockade at Paknam Yothaka on the Bangpakong River near Prachinburi. Thepphiphit's Eastern Siamese host was led by two local officials Muen Kao (Thai: หมื่นเก้า)^[10] and Muen Si Nawa (Thai: หมื่นศรีนาวา)^[10] from Prachinburi and a local leader Thongyu Noklek (Thai: ทองอยู่นกเล็ก)^[10] from Chonburi. Upon hearing about Thepphiphit's new host at Paknam Yothaka, Thepphiphit's family in Ayutthaya, including his wives, sons, daughter and servants, left Ayutthaya through the less-besieged eastern outskirts of Ayutthaya to join Thepphiphit at Prachinburi. A number of Ayutthayan people, having no hope in Ekkathat's regime, left Ayutthaya to join Thepphiphit. Phraya Rattanathibet the Minister of Palace Affairs and Ekkathat's many-time military commander, who had marched out against the Burmese in 1760 and 1765, also left Ayutthaya to join Thepphiphit. This showed that, in spite of political setbacks and many years of wandering, Thepphiphit still commanded a considerable loyalty in Ayutthaya and in Siam.

Thepphiphit's uprising was detrimental to Ekkathat as it deprived Ekkathat of manpower and officials, who simply went out to join Thepphiphit. It is not known whether Thepphiphit's intention of rising in 1766 was patriotic or political but Ekkathat would never trust his troublesome half-brother. Thepphiphit and his family stayed at Prachinburi while letting his subordinates Muen Kao, Muen Si Nawa and Thongyu Noklek to command his host at Paknam Yothaka. It was the Burmese who marched out from Ayutthaya to attack and defeat Thepphiphit's Eastern Siamese host at Paknam Yothaka. Muen Kao and Muen Si Nawa were killed in battle against the Burmese while Thongyu Noklek fled. Thepphiphit's host was eventually dispersed by the Burmese forces.

Thepphiphit, his family and Phraya Rattanathibet, upon learning about the fall of Paknam Yothaka, left Prachinburi to take refuge at Nakhon Ratchasima in the northeast. However, Phraya Rattanathibet fell ill and died on the way. Thepphiphit held a funeral for this minister who had shifted political allegiance from Ekkathat to Thepphiphit.